[PATCH V3] x86, UV: BAU performance and error recovery

[Cliff Wickman]

Ingo,
This patch updates the patch of the same name, which is in your lastest -tip
  b8f7fb1: x86, UV: Improve BAU performance and error recovery
It does not depend on any other patch.

It includes the BAU tunables interfaced through debugfs (instead of /proc)
per Greg Kroah-Hartman's recommendation.

This patch
- corrects several bugs:
  o the lack of BAU messaging to blade 0 (an uninitialized field)
  o correct message type for a normal shootdown message
  o fix to recovery from timed-out s/w acknowledge resources
  o calculation of the actual destination timeout so that a 'short' timeout can
    be identified
  o fix mishandling of non-consecutive hub and socket numbers
  o identification of a cpu's socket number
  o removal of the check for the h/w stay-busy bug, as under extreme pressure it
    cannot be accurately detected
  o fall back to IPI-method when extreme pressure makes numalink very slow,
    and then resume BAU-method after an interval
- adds BAU broadcasting to the cpu's on the local node
- simplifies the returning of the original cpu bitmap when the BAU attempt
  is given up entirely
- adds modification of tuning variables through debugfs
  (/sys/kernel/debug/sgi_uv/bau_tunables)

Peter, I weighed the review-ability of a patch for each bug fix and each
addition, versus the ease of tracking a single patch. And decided on the
latter since these bugs and features are only of interest to SGI UV. Hope
that is reasonable.

Diffed against 2.6.34 -tip  (Sheep on Meth)

Signed-off-by: Cliff Wickman <cpw@xxxxxxx>

---
 arch/x86/include/asm/uv/uv_bau.h |  306 +++++--
 arch/x86/kernel/tlb_uv.c         | 1586 +++++++++++++++++++++++++++++----------
 2 files changed, 1422 insertions(+), 470 deletions(-)

Index: 100524.linux.2.6.34/arch/x86/include/asm/uv/uv_bau.h
===================================================================
--- 100524.linux.2.6.34.orig/arch/x86/include/asm/uv/uv_bau.h
+++ 100524.linux.2.6.34/arch/x86/include/asm/uv/uv_bau.h
@@ -27,13 +27,15 @@
  * set 2 is at BASE + 2*512, set 3 at BASE + 3*512, and so on.
  *
  * We will use 31 sets, one for sending BAU messages from each of the 32
- * cpu's on the node.
+ * cpu's on the uvhub.
  *
  * TLB shootdown will use the first of the 8 descriptors of each set.
  * Each of the descriptors is 64 bytes in size (8*64 = 512 bytes in a set).
  */
 
 #define UV_ITEMS_PER_DESCRIPTOR		8
+/* the 'throttle' to prevent the hardware stay-busy bug */
+#define MAX_BAU_CONCURRENT		3
 #define UV_CPUS_PER_ACT_STATUS		32
 #define UV_ACT_STATUS_MASK		0x3
 #define UV_ACT_STATUS_SIZE		2
@@ -44,7 +46,26 @@
 #define UV_DESC_BASE_PNODE_SHIFT	49
 #define UV_PAYLOADQ_PNODE_SHIFT		49
 #define UV_PTC_BASENAME			"sgi_uv/ptc_statistics"
+#define UV_BAU_BASENAME			"sgi_uv/bau_tunables"
+#define UV_BAU_TUNABLES_DIR		"sgi_uv"
+#define UV_BAU_TUNABLES_FILE		"bau_tunables"
+#define WHITESPACE			" \t\n"
 #define uv_physnodeaddr(x)		((__pa((unsigned long)(x)) & uv_mmask))
+#define UV_ENABLE_INTD_SOFT_ACK_MODE_SHIFT 15
+#define UV_INTD_SOFT_ACK_TIMEOUT_PERIOD_SHIFT 16
+#define UV_INTD_SOFT_ACK_TIMEOUT_PERIOD 0x0000000009UL
+/* [19:16] SOFT_ACK timeout period  19: 1 is urgency 7  17:16 1 is multiplier */
+#define BAU_MISC_CONTROL_MULT_MASK 3
+
+#define UVH_AGING_PRESCALE_SEL 0x000000b000UL
+/* [30:28] URGENCY_7  an index into a table of times */
+#define BAU_URGENCY_7_SHIFT 28
+#define BAU_URGENCY_7_MASK 7
+
+#define UVH_TRANSACTION_TIMEOUT 0x000000b200UL
+/* [45:40] BAU - BAU transaction timeout select - a multiplier */
+#define BAU_TRANS_SHIFT 40
+#define BAU_TRANS_MASK 0x3f
 
 /*
  * bits in UVH_LB_BAU_SB_ACTIVATION_STATUS_0/1
@@ -55,15 +76,26 @@
 #define DESC_STATUS_SOURCE_TIMEOUT	3
 
 /*
- * source side thresholds at which message retries print a warning
+ * delay for 'plugged' timeout retries, in microseconds
  */
-#define SOURCE_TIMEOUT_LIMIT		20
-#define DESTINATION_TIMEOUT_LIMIT	20
+#define PLUGGED_DELAY			10
+
+/*
+ * threshholds at which to use IPI to free resources
+ */
+/* after this # consecutive 'plugged' timeouts, use IPI to release resources */
+#define PLUGSB4RESET 100
+/* after this many consecutive timeouts, use IPI to release resources */
+#define TIMEOUTSB4RESET 1
+/* at this number uses of IPI to release resources, giveup the request */
+#define IPI_RESET_LIMIT 1
+/* after this # consecutive successes, bump up the throttle if it was lowered */
+#define COMPLETE_THRESHOLD 5
 
 /*
  * number of entries in the destination side payload queue
  */
-#define DEST_Q_SIZE			17
+#define DEST_Q_SIZE			20
 /*
  * number of destination side software ack resources
  */
@@ -72,9 +104,17 @@
 /*
  * completion statuses for sending a TLB flush message
  */
-#define	FLUSH_RETRY			1
-#define	FLUSH_GIVEUP			2
-#define	FLUSH_COMPLETE			3
+#define FLUSH_RETRY_PLUGGED		1
+#define FLUSH_RETRY_TIMEOUT		2
+#define FLUSH_GIVEUP			3
+#define FLUSH_COMPLETE			4
+
+/*
+ * tuning the action when the numalink network is extremely delayed
+ */
+#define CONGESTED_RESPONSE_US 1000 /* 'long' response time, in microseconds */
+#define CONGESTED_REPS 10 /* long delays averaged over this many broadcasts */
+#define CONGESTED_PERIOD 30 /* time for the bau to be disabled, in seconds */
 
 /*
  * Distribution: 32 bytes (256 bits) (bytes 0-0x1f of descriptor)
@@ -86,14 +126,14 @@
  * 'base_dest_nodeid' field of the header corresponds to the
  * destination nodeID associated with that specified bit.
  */
-struct bau_target_nodemask {
-	unsigned long bits[BITS_TO_LONGS(256)];
+struct bau_target_uvhubmask {
+	unsigned long bits[BITS_TO_LONGS(UV_DISTRIBUTION_SIZE)];
 };
 
 /*
- * mask of cpu's on a node
+ * mask of cpu's on a uvhub
  * (during initialization we need to check that unsigned long has
- *  enough bits for max. cpu's per node)
+ *  enough bits for max. cpu's per uvhub)
  */
 struct bau_local_cpumask {
 	unsigned long bits;
@@ -135,8 +175,8 @@ struct bau_msg_payload {
 struct bau_msg_header {
 	unsigned int dest_subnodeid:6;	/* must be 0x10, for the LB */
 	/* bits 5:0 */
-	unsigned int base_dest_nodeid:15; /* nasid>>1 (pnode) of */
-	/* bits 20:6 */			  /* first bit in node_map */
+	unsigned int base_dest_nodeid:15; /* nasid (pnode<<1) of */
+	/* bits 20:6 */			  /* first bit in uvhub map */
 	unsigned int command:8;	/* message type */
 	/* bits 28:21 */
 				/* 0x38: SN3net EndPoint Message */
@@ -146,26 +186,38 @@ struct bau_msg_header {
 	unsigned int rsvd_2:9;	/* must be zero */
 	/* bits 40:32 */
 				/* Suppl_A is 56-41 */
-	unsigned int payload_2a:8;/* becomes byte 16 of msg */
-	/* bits 48:41 */	/* not currently using */
-	unsigned int payload_2b:8;/* becomes byte 17 of msg */
-	/* bits 56:49 */	/* not currently using */
+	unsigned int sequence:16;/* message sequence number */
+	/* bits 56:41 */	/* becomes bytes 16-17 of msg */
 				/* Address field (96:57) is never used as an
 				   address (these are address bits 42:3) */
+
 	unsigned int rsvd_3:1;	/* must be zero */
 	/* bit 57 */
 				/* address bits 27:4 are payload */
-				/* these 24 bits become bytes 12-14 of msg */
+	/* these next 24  (58-81) bits become bytes 12-14 of msg */
+
+	/* bits 65:58 land in byte 12 */
 	unsigned int replied_to:1;/* sent as 0 by the source to byte 12 */
 	/* bit 58 */
-
-	unsigned int payload_1a:5;/* not currently used */
-	/* bits 63:59 */
-	unsigned int payload_1b:8;/* not currently used */
-	/* bits 71:64 */
-	unsigned int payload_1c:8;/* not currently used */
-	/* bits 79:72 */
-	unsigned int payload_1d:2;/* not currently used */
+	unsigned int msg_type:3; /* software type of the message*/
+	/* bits 61:59 */
+	unsigned int canceled:1; /* message canceled, resource to be freed*/
+	/* bit 62 */
+	unsigned int payload_1a:1;/* not currently used */
+	/* bit 63 */
+	unsigned int payload_1b:2;/* not currently used */
+	/* bits 65:64 */
+
+	/* bits 73:66 land in byte 13 */
+	unsigned int payload_1ca:6;/* not currently used */
+	/* bits 71:66 */
+	unsigned int payload_1c:2;/* not currently used */
+	/* bits 73:72 */
+
+	/* bits 81:74 land in byte 14 */
+	unsigned int payload_1d:6;/* not currently used */
+	/* bits 79:74 */
+	unsigned int payload_1e:2;/* not currently used */
 	/* bits 81:80 */
 
 	unsigned int rsvd_4:7;	/* must be zero */
@@ -178,7 +230,7 @@ struct bau_msg_header {
 	/* bits 95:90 */
 	unsigned int rsvd_6:5;	/* must be zero */
 	/* bits 100:96 */
-	unsigned int int_both:1;/* if 1, interrupt both sockets on the blade */
+	unsigned int int_both:1;/* if 1, interrupt both sockets on the uvhub */
 	/* bit 101*/
 	unsigned int fairness:3;/* usually zero */
 	/* bits 104:102 */
@@ -191,13 +243,18 @@ struct bau_msg_header {
 	/* bits 127:107 */
 };
 
+/* see msg_type: */
+#define MSG_NOOP 0
+#define MSG_REGULAR 1
+#define MSG_RETRY 2
+
 /*
  * The activation descriptor:
  * The format of the message to send, plus all accompanying control
  * Should be 64 bytes
  */
 struct bau_desc {
-	struct bau_target_nodemask distribution;
+	struct bau_target_uvhubmask distribution;
 	/*
 	 * message template, consisting of header and payload:
 	 */
@@ -237,19 +294,25 @@ struct bau_payload_queue_entry {
 	unsigned short acknowledge_count; /* filled in by destination */
 	/* 16 bits, bytes 10-11 */
 
-	unsigned short replied_to:1;	/* sent as 0 by the source */
-	/* 1 bit */
-	unsigned short unused1:7;       /* not currently using */
-	/* 7 bits: byte 12) */
-
-	unsigned char unused2[2];	/* not currently using */
-	/* bytes 13-14 */
+	/* these next 3 bytes come from bits 58-81 of the message header */
+	unsigned short replied_to:1;    /* sent as 0 by the source */
+	unsigned short msg_type:3;      /* software message type */
+	unsigned short canceled:1;      /* sent as 0 by the source */
+	unsigned short unused1:3;       /* not currently using */
+	/* byte 12 */
+
+	unsigned char unused2a;		/* not currently using */
+	/* byte 13 */
+	unsigned char unused2;		/* not currently using */
+	/* byte 14 */
 
 	unsigned char sw_ack_vector;	/* filled in by the hardware */
 	/* byte 15 (bits 127:120) */
 
-	unsigned char unused4[3];	/* not currently using bytes 17-19 */
-	/* bytes 17-19 */
+	unsigned short sequence;	/* message sequence number */
+	/* bytes 16-17 */
+	unsigned char unused4[2];	/* not currently using bytes 18-19 */
+	/* bytes 18-19 */
 
 	int number_of_cpus;		/* filled in at destination */
 	/* 32 bits, bytes 20-23 (aligned) */
@@ -258,64 +321,126 @@ struct bau_payload_queue_entry {
 	/* bytes 24-31 */
 };
 
-/*
- * one for every slot in the destination payload queue
- */
-struct bau_msg_status {
-	struct bau_local_cpumask seen_by;	/* map of cpu's */
+struct msg_desc {
+	struct bau_payload_queue_entry *msg;
+	int msg_slot;
+	int sw_ack_slot;
+	struct bau_payload_queue_entry *va_queue_first;
+	struct bau_payload_queue_entry *va_queue_last;
+};
+
+struct reset_args {
+	int sender;
 };
 
 /*
- * one for every slot in the destination software ack resources
+ * This structure is allocated per_cpu for UV TLB shootdown statistics.
  */
-struct bau_sw_ack_status {
-	struct bau_payload_queue_entry *msg;	/* associated message */
-	int watcher;				/* cpu monitoring, or -1 */
+struct ptc_stats {
+	/* sender statistics */
+	unsigned long s_giveup; /* number of fall backs to IPI-style flushes */
+	unsigned long s_requestor; /* number of shootdown requests */
+	unsigned long s_stimeout; /* source side timeouts */
+	unsigned long s_dtimeout; /* destination side timeouts */
+	unsigned long s_time; /* time spent in sending side */
+	unsigned long s_retriesok; /* successful retries */
+	unsigned long s_ntargcpu; /* total number of cpu's targeted */
+	unsigned long s_ntargself; /* times the sending cpu was targeted */
+	unsigned long s_ntarglocals; /* targets of cpus on the local blade */
+	unsigned long s_ntargremotes; /* targets of cpus on remote blades */
+	unsigned long s_ntarglocaluvhub; /* targets of the local hub */
+	unsigned long s_ntargremoteuvhub; /* remotes hubs targeted */
+	unsigned long s_ntarguvhub; /* total number of uvhubs targeted */
+	unsigned long s_ntarguvhub16; /* number of times target hubs >= 16*/
+	unsigned long s_ntarguvhub8; /* number of times target hubs >= 8 */
+	unsigned long s_ntarguvhub4; /* number of times target hubs >= 4 */
+	unsigned long s_ntarguvhub2; /* number of times target hubs >= 2 */
+	unsigned long s_ntarguvhub1; /* number of times target hubs == 1 */
+	unsigned long s_resets_plug; /* ipi-style resets from plug state */
+	unsigned long s_resets_timeout; /* ipi-style resets from timeouts */
+	unsigned long s_busy; /* status stayed busy past s/w timer */
+	unsigned long s_throttles; /* waits in throttle */
+	unsigned long s_retry_messages; /* retry broadcasts */
+	unsigned long s_bau_reenabled; /* for bau enable/disable */
+	unsigned long s_bau_disabled; /* for bau enable/disable */
+	/* destination statistics */
+	unsigned long d_alltlb; /* times all tlb's on this cpu were flushed */
+	unsigned long d_onetlb; /* times just one tlb on this cpu was flushed */
+	unsigned long d_multmsg; /* interrupts with multiple messages */
+	unsigned long d_nomsg; /* interrupts with no message */
+	unsigned long d_time; /* time spent on destination side */
+	unsigned long d_requestee; /* number of messages processed */
+	unsigned long d_retries; /* number of retry messages processed */
+	unsigned long d_canceled; /* number of messages canceled by retries */
+	unsigned long d_nocanceled; /* retries that found nothing to cancel */
+	unsigned long d_resets; /* number of ipi-style requests processed */
+	unsigned long d_rcanceled; /* number of messages canceled by resets */
 };
 
 /*
- * one on every node and per-cpu; to locate the software tables
+ * one per-cpu; to locate the software tables
  */
 struct bau_control {
 	struct bau_desc *descriptor_base;
-	struct bau_payload_queue_entry *bau_msg_head;
 	struct bau_payload_queue_entry *va_queue_first;
 	struct bau_payload_queue_entry *va_queue_last;
-	struct bau_msg_status *msg_statuses;
-	int *watching; /* pointer to array */
-};
-
-/*
- * This structure is allocated per_cpu for UV TLB shootdown statistics.
- */
-struct ptc_stats {
-	unsigned long ptc_i;	/* number of IPI-style flushes */
-	unsigned long requestor;	/* number of nodes this cpu sent to */
-	unsigned long requestee;	/* times cpu was remotely requested */
-	unsigned long alltlb;	/* times all tlb's on this cpu were flushed */
-	unsigned long onetlb;	/* times just one tlb on this cpu was flushed */
-	unsigned long s_retry;	/* retries on source side timeouts */
-	unsigned long d_retry;	/* retries on destination side timeouts */
-	unsigned long sflush;	/* cycles spent in uv_flush_tlb_others */
-	unsigned long dflush;	/* cycles spent on destination side */
-	unsigned long retriesok; /* successes on retries */
-	unsigned long nomsg;	/* interrupts with no message */
-	unsigned long multmsg;	/* interrupts with multiple messages */
-	unsigned long ntargeted;/* nodes targeted */
+	struct bau_payload_queue_entry *bau_msg_head;
+	struct bau_control *uvhub_master;
+	struct bau_control *socket_master;
+	struct ptc_stats *statp;
+	unsigned long timeout_interval;
+	unsigned long set_bau_on_time;
+	atomic_t active_descriptor_count;
+	int plugged_tries;
+	int timeout_tries;
+	int ipi_attempts;
+	int conseccompletes;
+	int baudisabled;
+	int set_bau_off;
+	short cpu;
+	short uvhub_cpu;
+	short uvhub;
+	short cpus_in_socket;
+	short cpus_in_uvhub;
+	unsigned short message_number;
+	unsigned short uvhub_quiesce;
+	short socket_acknowledge_count[DEST_Q_SIZE];
+	cycles_t send_message;
+	spinlock_t uvhub_lock;
+	spinlock_t queue_lock;
+	/* tunables */
+	int max_bau_concurrent;
+	int max_bau_concurrent_constant;
+	int plugged_delay;
+	int plugsb4reset;
+	int timeoutsb4reset;
+	int ipi_reset_limit;
+	int complete_threshold;
+	int congested_response_us;
+	int congested_reps;
+	int congested_period;
+	cycles_t period_time;
+	long period_requests;
 };
 
-static inline int bau_node_isset(int node, struct bau_target_nodemask *dstp)
+static inline int bau_uvhub_isset(int uvhub, struct bau_target_uvhubmask *dstp)
 {
-	return constant_test_bit(node, &dstp->bits[0]);
+	return constant_test_bit(uvhub, &dstp->bits[0]);
 }
-static inline void bau_node_set(int node, struct bau_target_nodemask *dstp)
+static inline void bau_uvhub_set(int uvhub, struct bau_target_uvhubmask *dstp)
 {
-	__set_bit(node, &dstp->bits[0]);
+	__set_bit(uvhub, &dstp->bits[0]);
 }
-static inline void bau_nodes_clear(struct bau_target_nodemask *dstp, int nbits)
+static inline void bau_uvhubs_clear(struct bau_target_uvhubmask *dstp,
+				    int nbits)
 {
 	bitmap_zero(&dstp->bits[0], nbits);
 }
+static inline int bau_uvhub_weight(struct bau_target_uvhubmask *dstp)
+{
+	return bitmap_weight((unsigned long *)&dstp->bits[0],
+				UV_DISTRIBUTION_SIZE);
+}
 
 static inline void bau_cpubits_clear(struct bau_local_cpumask *dstp, int nbits)
 {
@@ -328,4 +453,35 @@ static inline void bau_cpubits_clear(str
 extern void uv_bau_message_intr1(void);
 extern void uv_bau_timeout_intr1(void);
 
+struct atomic_short {
+	short counter;
+};
+
+/**
+ * atomic_read_short - read a short atomic variable
+ * @v: pointer of type atomic_short
+ *
+ * Atomically reads the value of @v.
+ */
+static inline int atomic_read_short(const struct atomic_short *v)
+{
+	return v->counter;
+}
+
+/**
+ * atomic_add_short_return - add and return a short int
+ * @i: short value to add
+ * @v: pointer of type atomic_short
+ *
+ * Atomically adds @i to @v and returns @i + @v
+ */
+static inline int atomic_add_short_return(short i, struct atomic_short *v)
+{
+	short __i = i;
+	asm volatile(LOCK_PREFIX "xaddw %0, %1"
+			: "+r" (i), "+m" (v->counter)
+			: : "memory");
+	return i + __i;
+}
+
 #endif /* _ASM_X86_UV_UV_BAU_H */
Index: 100524.linux.2.6.34/arch/x86/kernel/tlb_uv.c
===================================================================
--- 100524.linux.2.6.34.orig/arch/x86/kernel/tlb_uv.c
+++ 100524.linux.2.6.34/arch/x86/kernel/tlb_uv.c
@@ -1,15 +1,15 @@
 /*
  *	SGI UltraViolet TLB flush routines.
  *
- *	(c) 2008 Cliff Wickman <cpw@xxxxxxx>, SGI.
+ *	(c) 2008-2010 Cliff Wickman <cpw@xxxxxxx>, SGI.
  *
  *	This code is released under the GNU General Public License version 2 or
  *	later.
  */
 #include <linux/seq_file.h>
 #include <linux/proc_fs.h>
+#include <linux/debugfs.h>
 #include <linux/kernel.h>
-#include <linux/slab.h>
 
 #include <asm/mmu_context.h>
 #include <asm/uv/uv.h>
@@ -20,42 +20,81 @@
 #include <asm/idle.h>
 #include <asm/tsc.h>
 #include <asm/irq_vectors.h>
+#include <asm/timer.h>
 
-static struct bau_control	**uv_bau_table_bases __read_mostly;
-static int			uv_bau_retry_limit __read_mostly;
+/* timeouts in nanoseconds (indexed by UVH_AGING_PRESCALE_SEL urgency7 30:28) */
+static int timeout_base_ns[] = {
+		20,
+		160,
+		1280,
+		10240,
+		81920,
+		655360,
+		5242880,
+		167772160
+};
+static int timeout_us;
+static int nobau;
+static int baudisabled;
+static spinlock_t disable_lock;
+static cycles_t congested_cycles;
+
+/* tunables: */
+static int max_bau_concurrent = MAX_BAU_CONCURRENT;
+static int max_bau_concurrent_constant = MAX_BAU_CONCURRENT;
+static int plugged_delay = PLUGGED_DELAY;
+static int plugsb4reset = PLUGSB4RESET;
+static int timeoutsb4reset = TIMEOUTSB4RESET;
+static int ipi_reset_limit = IPI_RESET_LIMIT;
+static int complete_threshold = COMPLETE_THRESHOLD;
+static int congested_response_us = CONGESTED_RESPONSE_US;
+static int congested_reps = CONGESTED_REPS;
+static int congested_period = CONGESTED_PERIOD;
+static struct dentry *tunables_dir;
+static struct dentry *tunables_file;
 
-/* base pnode in this partition */
-static int			uv_partition_base_pnode __read_mostly;
+static int __init setup_nobau(char *arg)
+{
+	nobau = 1;
+	return 0;
+}
+early_param("nobau", setup_nobau);
 
-static unsigned long		uv_mmask __read_mostly;
+/* base pnode in this partition */
+static int uv_partition_base_pnode __read_mostly;
+/* position of pnode (which is nasid>>1): */
+static int uv_nshift __read_mostly;
+static unsigned long uv_mmask __read_mostly;
 
 static DEFINE_PER_CPU(struct ptc_stats, ptcstats);
 static DEFINE_PER_CPU(struct bau_control, bau_control);
+static DEFINE_PER_CPU(cpumask_var_t, uv_flush_tlb_mask);
 
 /*
- * Determine the first node on a blade.
+ * Determine the first node on a uvhub. 'Nodes' are used for kernel
+ * memory allocation.
  */
-static int __init blade_to_first_node(int blade)
+static int __init uvhub_to_first_node(int uvhub)
 {
 	int node, b;
 
 	for_each_online_node(node) {
 		b = uv_node_to_blade_id(node);
-		if (blade == b)
+		if (uvhub == b)
 			return node;
 	}
-	return -1; /* shouldn't happen */
+	return -1;
 }
 
 /*
- * Determine the apicid of the first cpu on a blade.
+ * Determine the apicid of the first cpu on a uvhub.
  */
-static int __init blade_to_first_apicid(int blade)
+static int __init uvhub_to_first_apicid(int uvhub)
 {
 	int cpu;
 
 	for_each_present_cpu(cpu)
-		if (blade == uv_cpu_to_blade_id(cpu))
+		if (uvhub == uv_cpu_to_blade_id(cpu))
 			return per_cpu(x86_cpu_to_apicid, cpu);
 	return -1;
 }
@@ -68,195 +107,432 @@ static int __init blade_to_first_apicid(
  * clear of the Timeout bit (as well) will free the resource. No reply will
  * be sent (the hardware will only do one reply per message).
  */
-static void uv_reply_to_message(int resource,
-				struct bau_payload_queue_entry *msg,
-				struct bau_msg_status *msp)
+static inline void uv_reply_to_message(struct msg_desc *mdp,
+				       struct bau_control *bcp)
 {
 	unsigned long dw;
+	struct bau_payload_queue_entry *msg;
 
-	dw = (1 << (resource + UV_SW_ACK_NPENDING)) | (1 << resource);
+	msg = mdp->msg;
+	if (!msg->canceled) {
+		dw = (msg->sw_ack_vector << UV_SW_ACK_NPENDING) |
+						msg->sw_ack_vector;
+		uv_write_local_mmr(
+				UVH_LB_BAU_INTD_SOFTWARE_ACKNOWLEDGE_ALIAS, dw);
+	}
 	msg->replied_to = 1;
 	msg->sw_ack_vector = 0;
-	if (msp)
-		msp->seen_by.bits = 0;
-	uv_write_local_mmr(UVH_LB_BAU_INTD_SOFTWARE_ACKNOWLEDGE_ALIAS, dw);
 }
 
 /*
- * Do all the things a cpu should do for a TLB shootdown message.
- * Other cpu's may come here at the same time for this message.
+ * Process the receipt of a RETRY message
  */
-static void uv_bau_process_message(struct bau_payload_queue_entry *msg,
-				   int msg_slot, int sw_ack_slot)
+static inline void uv_bau_process_retry_msg(struct msg_desc *mdp,
+					    struct bau_control *bcp)
 {
-	unsigned long this_cpu_mask;
-	struct bau_msg_status *msp;
-	int cpu;
+	int i;
+	int cancel_count = 0;
+	int slot2;
+	unsigned long msg_res;
+	unsigned long mmr = 0;
+	struct bau_payload_queue_entry *msg;
+	struct bau_payload_queue_entry *msg2;
+	struct ptc_stats *stat;
 
-	msp = __get_cpu_var(bau_control).msg_statuses + msg_slot;
-	cpu = uv_blade_processor_id();
-	msg->number_of_cpus =
-		uv_blade_nr_online_cpus(uv_node_to_blade_id(numa_node_id()));
-	this_cpu_mask = 1UL << cpu;
-	if (msp->seen_by.bits & this_cpu_mask)
-		return;
-	atomic_or_long(&msp->seen_by.bits, this_cpu_mask);
+	msg = mdp->msg;
+	stat = bcp->statp;
+	stat->d_retries++;
+	/*
+	 * cancel any message from msg+1 to the retry itself
+	 */
+	for (msg2 = msg+1, i = 0; i < DEST_Q_SIZE; msg2++, i++) {
+		if (msg2 > mdp->va_queue_last)
+			msg2 = mdp->va_queue_first;
+		if (msg2 == msg)
+			break;
+
+		/* same conditions for cancellation as uv_do_reset */
+		if ((msg2->replied_to == 0) && (msg2->canceled == 0) &&
+		    (msg2->sw_ack_vector) && ((msg2->sw_ack_vector &
+			msg->sw_ack_vector) == 0) &&
+		    (msg2->sending_cpu == msg->sending_cpu) &&
+		    (msg2->msg_type != MSG_NOOP)) {
+			slot2 = msg2 - mdp->va_queue_first;
+			mmr = uv_read_local_mmr
+				(UVH_LB_BAU_INTD_SOFTWARE_ACKNOWLEDGE);
+			msg_res = msg2->sw_ack_vector;
+			/*
+			 * This is a message retry; clear the resources held
+			 * by the previous message only if they timed out.
+			 * If it has not timed out we have an unexpected
+			 * situation to report.
+			 */
+			if (mmr & (msg_res << UV_SW_ACK_NPENDING)) {
+				/*
+				 * is the resource timed out?
+				 * make everyone ignore the cancelled message.
+				 */
+				msg2->canceled = 1;
+				stat->d_canceled++;
+				cancel_count++;
+				uv_write_local_mmr(
+				    UVH_LB_BAU_INTD_SOFTWARE_ACKNOWLEDGE_ALIAS,
+					(msg_res << UV_SW_ACK_NPENDING) |
+					 msg_res);
+			}
+		}
+	}
+	if (!cancel_count)
+		stat->d_nocanceled++;
+}
 
-	if (msg->replied_to == 1)
-		return;
+/*
+ * Do all the things a cpu should do for a TLB shootdown message.
+ * Other cpu's may come here at the same time for this message.
+ */
+static void uv_bau_process_message(struct msg_desc *mdp,
+				   struct bau_control *bcp)
+{
+	int msg_ack_count;
+	short socket_ack_count = 0;
+	struct ptc_stats *stat;
+	struct bau_payload_queue_entry *msg;
+	struct bau_control *smaster = bcp->socket_master;
 
+	/*
+	 * This must be a normal message, or retry of a normal message
+	 */
+	msg = mdp->msg;
+	stat = bcp->statp;
 	if (msg->address == TLB_FLUSH_ALL) {
 		local_flush_tlb();
-		__get_cpu_var(ptcstats).alltlb++;
+		stat->d_alltlb++;
 	} else {
 		__flush_tlb_one(msg->address);
-		__get_cpu_var(ptcstats).onetlb++;
+		stat->d_onetlb++;
 	}
+	stat->d_requestee++;
 
-	__get_cpu_var(ptcstats).requestee++;
+	/*
+	 * One cpu on each uvhub has the additional job on a RETRY
+	 * of releasing the resource held by the message that is
+	 * being retried.  That message is identified by sending
+	 * cpu number.
+	 */
+	if (msg->msg_type == MSG_RETRY && bcp == bcp->uvhub_master)
+		uv_bau_process_retry_msg(mdp, bcp);
+
+	/*
+	 * This is a sw_ack message, so we have to reply to it.
+	 * Count each responding cpu on the socket. This avoids
+	 * pinging the count's cache line back and forth between
+	 * the sockets.
+	 */
+	socket_ack_count = atomic_add_short_return(1, (struct atomic_short *)
+			&smaster->socket_acknowledge_count[mdp->msg_slot]);
+	if (socket_ack_count == bcp->cpus_in_socket) {
+		/*
+		 * Both sockets dump their completed count total into
+		 * the message's count.
+		 */
+		smaster->socket_acknowledge_count[mdp->msg_slot] = 0;
+		msg_ack_count = atomic_add_short_return(socket_ack_count,
+				(struct atomic_short *)&msg->acknowledge_count);
+
+		if (msg_ack_count == bcp->cpus_in_uvhub) {
+			/*
+			 * All cpus in uvhub saw it; reply
+			 */
+			uv_reply_to_message(mdp, bcp);
+		}
+	}
 
-	atomic_inc_short(&msg->acknowledge_count);
-	if (msg->number_of_cpus == msg->acknowledge_count)
-		uv_reply_to_message(sw_ack_slot, msg, msp);
+	return;
 }
 
 /*
- * Examine the payload queue on one distribution node to see
- * which messages have not been seen, and which cpu(s) have not seen them.
+ * Determine the first cpu on a uvhub.
+ */
+static int uvhub_to_first_cpu(int uvhub)
+{
+	int cpu;
+	for_each_present_cpu(cpu)
+		if (uvhub == uv_cpu_to_blade_id(cpu))
+			return cpu;
+	return -1;
+}
+
+/*
+ * Last resort when we get a large number of destination timeouts is
+ * to clear resources held by a given cpu.
+ * Do this with IPI so that all messages in the BAU message queue
+ * can be identified by their nonzero sw_ack_vector field.
  *
- * Returns the number of cpu's that have not responded.
+ * This is entered for a single cpu on the uvhub.
+ * The sender want's this uvhub to free a specific message's
+ * sw_ack resources.
  */
-static int uv_examine_destination(struct bau_control *bau_tablesp, int sender)
+static void
+uv_do_reset(void *ptr)
 {
-	struct bau_payload_queue_entry *msg;
-	struct bau_msg_status *msp;
-	int count = 0;
 	int i;
-	int j;
+	int slot;
+	int count = 0;
+	unsigned long mmr;
+	unsigned long msg_res;
+	struct bau_control *bcp;
+	struct reset_args *rap;
+	struct bau_payload_queue_entry *msg;
+	struct ptc_stats *stat;
 
-	for (msg = bau_tablesp->va_queue_first, i = 0; i < DEST_Q_SIZE;
-	     msg++, i++) {
-		if ((msg->sending_cpu == sender) && (!msg->replied_to)) {
-			msp = bau_tablesp->msg_statuses + i;
-			printk(KERN_DEBUG
-			       "blade %d: address:%#lx %d of %d, not cpu(s): ",
-			       i, msg->address, msg->acknowledge_count,
-			       msg->number_of_cpus);
-			for (j = 0; j < msg->number_of_cpus; j++) {
-				if (!((1L << j) & msp->seen_by.bits)) {
-					count++;
-					printk("%d ", j);
-				}
+	bcp = &per_cpu(bau_control, smp_processor_id());
+	rap = (struct reset_args *)ptr;
+	stat = bcp->statp;
+	stat->d_resets++;
+
+	/*
+	 * We're looking for the given sender, and
+	 * will free its sw_ack resource.
+	 * If all cpu's finally responded after the timeout, its
+	 * message 'replied_to' was set.
+	 */
+	for (msg = bcp->va_queue_first, i = 0; i < DEST_Q_SIZE; msg++, i++) {
+		/* uv_do_reset: same conditions for cancellation as
+		   uv_bau_process_retry_msg() */
+		if ((msg->replied_to == 0) &&
+		    (msg->canceled == 0) &&
+		    (msg->sending_cpu == rap->sender) &&
+		    (msg->sw_ack_vector) &&
+		    (msg->msg_type != MSG_NOOP)) {
+			/*
+			 * make everyone else ignore this message
+			 */
+			msg->canceled = 1;
+			slot = msg - bcp->va_queue_first;
+			count++;
+			/*
+			 * only reset the resource if it is still pending
+			 */
+			mmr = uv_read_local_mmr
+					(UVH_LB_BAU_INTD_SOFTWARE_ACKNOWLEDGE);
+			msg_res = msg->sw_ack_vector;
+			if (mmr & msg_res) {
+				stat->d_rcanceled++;
+				uv_write_local_mmr(
+				    UVH_LB_BAU_INTD_SOFTWARE_ACKNOWLEDGE_ALIAS,
+					(msg_res << UV_SW_ACK_NPENDING) |
+					 msg_res);
 			}
-			printk("\n");
 		}
 	}
-	return count;
+	return;
 }
 
 /*
- * Examine the payload queue on all the distribution nodes to see
- * which messages have not been seen, and which cpu(s) have not seen them.
- *
- * Returns the number of cpu's that have not responded.
+ * Use IPI to get all target uvhubs to release resources held by
+ * a given sending cpu number.
  */
-static int uv_examine_destinations(struct bau_target_nodemask *distribution)
+static void uv_reset_with_ipi(struct bau_target_uvhubmask *distribution,
+			      int sender)
 {
-	int sender;
-	int i;
-	int count = 0;
+	int uvhub;
+	int cpu;
+	cpumask_t mask;
+	struct reset_args reset_args;
+
+	reset_args.sender = sender;
 
-	sender = smp_processor_id();
-	for (i = 0; i < sizeof(struct bau_target_nodemask) * BITSPERBYTE; i++) {
-		if (!bau_node_isset(i, distribution))
+	cpus_clear(mask);
+	/* find a single cpu for each uvhub in this distribution mask */
+	for (uvhub = 0;
+		    uvhub < sizeof(struct bau_target_uvhubmask) * BITSPERBYTE;
+		    uvhub++) {
+		if (!bau_uvhub_isset(uvhub, distribution))
 			continue;
-		count += uv_examine_destination(uv_bau_table_bases[i], sender);
+		/* find a cpu for this uvhub */
+		cpu = uvhub_to_first_cpu(uvhub);
+		cpu_set(cpu, mask);
 	}
-	return count;
+	/* IPI all cpus; Preemption is already disabled */
+	smp_call_function_many(&mask, uv_do_reset, (void *)&reset_args, 1);
+	return;
+}
+
+static inline unsigned long
+cycles_2_us(unsigned long long cyc)
+{
+	unsigned long long ns;
+	unsigned long us;
+	ns =  (cyc * per_cpu(cyc2ns, smp_processor_id()))
+						>> CYC2NS_SCALE_FACTOR;
+	us = ns / 1000;
+	return us;
 }
 
 /*
- * wait for completion of a broadcast message
- *
- * return COMPLETE, RETRY or GIVEUP
+ * wait for all cpus on this hub to finish their sends and go quiet
+ * leaves uvhub_quiesce set so that no new broadcasts are started by
+ * bau_flush_send_and_wait()
+ */
+static inline void
+quiesce_local_uvhub(struct bau_control *hmaster)
+{
+	atomic_add_short_return(1, (struct atomic_short *)
+		 &hmaster->uvhub_quiesce);
+}
+
+/*
+ * mark this quiet-requestor as done
+ */
+static inline void
+end_uvhub_quiesce(struct bau_control *hmaster)
+{
+	atomic_add_short_return(-1, (struct atomic_short *)
+		&hmaster->uvhub_quiesce);
+}
+
+/*
+ * Wait for completion of a broadcast software ack message
+ * return COMPLETE, RETRY(PLUGGED or TIMEOUT) or GIVEUP
  */
 static int uv_wait_completion(struct bau_desc *bau_desc,
-			      unsigned long mmr_offset, int right_shift)
+	unsigned long mmr_offset, int right_shift, int this_cpu,
+	struct bau_control *bcp, struct bau_control *smaster, long try)
 {
-	int exams = 0;
-	long destination_timeouts = 0;
-	long source_timeouts = 0;
 	unsigned long descriptor_status;
+	cycles_t ttime;
+	struct ptc_stats *stat = bcp->statp;
+	struct bau_control *hmaster;
 
+	hmaster = bcp->uvhub_master;
+
+	/* spin on the status MMR, waiting for it to go idle */
 	while ((descriptor_status = (((unsigned long)
 		uv_read_local_mmr(mmr_offset) >>
 			right_shift) & UV_ACT_STATUS_MASK)) !=
 			DESC_STATUS_IDLE) {
-		if (descriptor_status == DESC_STATUS_SOURCE_TIMEOUT) {
-			source_timeouts++;
-			if (source_timeouts > SOURCE_TIMEOUT_LIMIT)
-				source_timeouts = 0;
-			__get_cpu_var(ptcstats).s_retry++;
-			return FLUSH_RETRY;
-		}
 		/*
-		 * spin here looking for progress at the destinations
+		 * Our software ack messages may be blocked because there are
+		 * no swack resources available.  As long as none of them
+		 * has timed out hardware will NACK our message and its
+		 * state will stay IDLE.
 		 */
-		if (descriptor_status == DESC_STATUS_DESTINATION_TIMEOUT) {
-			destination_timeouts++;
-			if (destination_timeouts > DESTINATION_TIMEOUT_LIMIT) {
-				/*
-				 * returns number of cpus not responding
-				 */
-				if (uv_examine_destinations
-				    (&bau_desc->distribution) == 0) {
-					__get_cpu_var(ptcstats).d_retry++;
-					return FLUSH_RETRY;
-				}
-				exams++;
-				if (exams >= uv_bau_retry_limit) {
-					printk(KERN_DEBUG
-					       "uv_flush_tlb_others");
-					printk("giving up on cpu %d\n",
-					       smp_processor_id());
-					return FLUSH_GIVEUP;
-				}
-				/*
-				 * delays can hang the simulator
-				   udelay(1000);
-				 */
-				destination_timeouts = 0;
+		if (descriptor_status == DESC_STATUS_SOURCE_TIMEOUT) {
+			stat->s_stimeout++;
+			return FLUSH_GIVEUP;
+		} else if (descriptor_status ==
+					DESC_STATUS_DESTINATION_TIMEOUT) {
+			stat->s_dtimeout++;
+			ttime = get_cycles();
+
+			/*
+			 * Our retries may be blocked by all destination
+			 * swack resources being consumed, and a timeout
+			 * pending.  In that case hardware returns the
+			 * ERROR that looks like a destination timeout.
+			 */
+			if (cycles_2_us(ttime - bcp->send_message) <
+							timeout_us) {
+				bcp->conseccompletes = 0;
+				return FLUSH_RETRY_PLUGGED;
 			}
+
+			bcp->conseccompletes = 0;
+			return FLUSH_RETRY_TIMEOUT;
+		} else {
+			/*
+			 * descriptor_status is still BUSY
+			 */
+			cpu_relax();
 		}
-		cpu_relax();
 	}
+	bcp->conseccompletes++;
 	return FLUSH_COMPLETE;
 }
 
+static inline cycles_t
+sec_2_cycles(unsigned long sec)
+{
+	unsigned long ns;
+	cycles_t cyc;
+
+	ns = sec * 1000000000;
+	cyc = (ns << CYC2NS_SCALE_FACTOR)/(per_cpu(cyc2ns, smp_processor_id()));
+	return cyc;
+}
+
+/*
+ * conditionally add 1 to *v, unless *v is >= u
+ * return 0 if we cannot add 1 to *v because it is >= u
+ * return 1 if we can add 1 to *v because it is < u
+ * the add is atomic
+ *
+ * This is close to atomic_add_unless(), but this allows the 'u' value
+ * to be lowered below the current 'v'.  atomic_add_unless can only stop
+ * on equal.
+ */
+static inline int atomic_inc_unless_ge(spinlock_t *lock, atomic_t *v, int u)
+{
+	spin_lock(lock);
+	if (atomic_read(v) >= u) {
+		spin_unlock(lock);
+		return 0;
+	}
+	atomic_inc(v);
+	spin_unlock(lock);
+	return 1;
+}
+
 /**
  * uv_flush_send_and_wait
  *
- * Send a broadcast and wait for a broadcast message to complete.
+ * Send a broadcast and wait for it to complete.
  *
- * The flush_mask contains the cpus the broadcast was sent to.
+ * The flush_mask contains the cpus the broadcast is to be sent to including
+ * cpus that are on the local uvhub.
  *
- * Returns NULL if all remote flushing was done. The mask is zeroed.
- * Returns @flush_mask if some remote flushing remains to be done. The
- * mask will have some bits still set.
+ * Returns 0 if all flushing represented in the mask was done.
+ * Returns 1 if it gives up entirely and the original cpu mask is to be
+ * returned to the kernel.
  */
-const struct cpumask *uv_flush_send_and_wait(int cpu, int this_pnode,
-					     struct bau_desc *bau_desc,
-					     struct cpumask *flush_mask)
+int uv_flush_send_and_wait(struct bau_desc *bau_desc,
+			   struct cpumask *flush_mask, struct bau_control *bcp)
 {
-	int completion_status = 0;
 	int right_shift;
-	int tries = 0;
-	int pnode;
-	int bit;
+	int completion_status = 0;
+	int seq_number = 0;
+	long try = 0;
+	int cpu = bcp->uvhub_cpu;
+	int tcpu;
+	int this_cpu = bcp->cpu;
 	unsigned long mmr_offset;
 	unsigned long index;
 	cycles_t time1;
 	cycles_t time2;
+	cycles_t elapsed;
+	cycles_t local_congested_cycles = congested_cycles;
+	struct ptc_stats *stat = bcp->statp;
+	struct bau_control *smaster = bcp->socket_master;
+	struct bau_control *hmaster = bcp->uvhub_master;
+	struct bau_control *tbcp;
+
+	/*
+	 * Spin here while there are hmaster->max_bau_concurrent or more active
+	 * descriptors. This is the per-uvhub 'throttle'.
+	 */
+	if (!atomic_inc_unless_ge(&hmaster->uvhub_lock,
+			&hmaster->active_descriptor_count,
+			hmaster->max_bau_concurrent)) {
+		stat->s_throttles++;
+		do {
+			cpu_relax();
+		} while (!atomic_inc_unless_ge(&hmaster->uvhub_lock,
+			&hmaster->active_descriptor_count,
+			hmaster->max_bau_concurrent));
+	}
+
+	while (hmaster->uvhub_quiesce)
+		cpu_relax();
 
 	if (cpu < UV_CPUS_PER_ACT_STATUS) {
 		mmr_offset = UVH_LB_BAU_SB_ACTIVATION_STATUS_0;
@@ -268,44 +544,147 @@ const struct cpumask *uv_flush_send_and_
 	}
 	time1 = get_cycles();
 	do {
-		tries++;
+		/*
+		 * Every message from any given cpu gets a unique message
+		 * sequence number. But retries use that same number.
+		 * Our message may have timed out at the destination because
+		 * all sw-ack resources are in use and there is a timeout
+		 * pending there.  In that case, our last send never got
+		 * placed into the queue and we need to persist until it
+		 * does.
+		 *
+		 * Make any retry a type MSG_RETRY so that the destination will
+		 * free any resource held by a previous message from this cpu.
+		 */
+		if (try == 0) {
+			bau_desc->header.msg_type = MSG_REGULAR;
+			seq_number = bcp->message_number++;
+		} else {
+			bau_desc->header.msg_type = MSG_RETRY;
+			stat->s_retry_messages++;
+		}
+		bau_desc->header.sequence = seq_number;
 		index = (1UL << UVH_LB_BAU_SB_ACTIVATION_CONTROL_PUSH_SHFT) |
-			cpu;
+			bcp->uvhub_cpu;
+		bcp->send_message = get_cycles();
+
 		uv_write_local_mmr(UVH_LB_BAU_SB_ACTIVATION_CONTROL, index);
+
+		try++;
 		completion_status = uv_wait_completion(bau_desc, mmr_offset,
-					right_shift);
-	} while (completion_status == FLUSH_RETRY);
+			right_shift, this_cpu, bcp, smaster, try);
+
+		if (completion_status == FLUSH_RETRY_PLUGGED) {
+			/*
+			 * Our retries may be blocked by all destination swack
+			 * resources being consumed, and a timeout pending. In
+			 * that case hardware immediately returns the ERROR
+			 * that looks like a destination timeout.
+			 */
+			udelay(bcp->plugged_delay);
+			bcp->plugged_tries++;
+			if (bcp->plugged_tries >= bcp->plugsb4reset) {
+				bcp->plugged_tries = 0;
+				quiesce_local_uvhub(hmaster);
+				spin_lock(&hmaster->queue_lock);
+				uv_reset_with_ipi(&bau_desc->distribution,
+							this_cpu);
+				spin_unlock(&hmaster->queue_lock);
+				end_uvhub_quiesce(hmaster);
+				bcp->ipi_attempts++;
+				stat->s_resets_plug++;
+			}
+		} else if (completion_status == FLUSH_RETRY_TIMEOUT) {
+			hmaster->max_bau_concurrent = 1;
+			bcp->timeout_tries++;
+			if (bcp->timeout_tries >= bcp->timeoutsb4reset) {
+				bcp->timeout_tries = 0;
+				quiesce_local_uvhub(hmaster);
+				spin_lock(&hmaster->queue_lock);
+				uv_reset_with_ipi(&bau_desc->distribution,
+								this_cpu);
+				spin_unlock(&hmaster->queue_lock);
+				end_uvhub_quiesce(hmaster);
+				bcp->ipi_attempts++;
+				stat->s_resets_timeout++;
+			}
+		}
+		if (bcp->ipi_attempts >= bcp->ipi_reset_limit) {
+			bcp->ipi_attempts = 0;
+			completion_status = FLUSH_GIVEUP;
+			break;
+		}
+		cpu_relax();
+	} while ((completion_status == FLUSH_RETRY_PLUGGED) ||
+		 (completion_status == FLUSH_RETRY_TIMEOUT));
 	time2 = get_cycles();
-	__get_cpu_var(ptcstats).sflush += (time2 - time1);
-	if (tries > 1)
-		__get_cpu_var(ptcstats).retriesok++;
 
-	if (completion_status == FLUSH_GIVEUP) {
+	bcp->plugged_tries = 0;
+	bcp->timeout_tries = 0;
+
+	if ((completion_status == FLUSH_COMPLETE) &&
+	    (bcp->conseccompletes > bcp->complete_threshold) &&
+	    (hmaster->max_bau_concurrent <
+					hmaster->max_bau_concurrent_constant))
+			hmaster->max_bau_concurrent++;
+
+	/*
+	 * hold any cpu not timing out here; no other cpu currently held by
+	 * the 'throttle' should enter the activation code
+	 */
+	while (hmaster->uvhub_quiesce)
+		cpu_relax();
+	atomic_dec(&hmaster->active_descriptor_count);
+
+	/* guard against cycles wrap */
+	if (time2 > time1) {
+		elapsed = time2 - time1;
+		stat->s_time += elapsed;
+		/* check for a sustained long, non-timeout request times */
+		if ((completion_status == FLUSH_COMPLETE) && (try == 1)) {
+			bcp->period_requests++;
+			bcp->period_time += elapsed;
+			if ((elapsed > local_congested_cycles) &&
+			    (bcp->period_requests > bcp->congested_reps)) {
+				/* let only one cpu do this disabling */
+				spin_lock(&disable_lock);
+				if (!baudisabled && bcp->period_requests &&
+				    ((bcp->period_time / bcp->period_requests) >
+						local_congested_cycles)) {
+					/* it becomes this cpu's job to turn
+					   on the use of the BAU again */
+					baudisabled = 1;
+					bcp->set_bau_off = 1;
+					bcp->set_bau_on_time = get_cycles() +
+					sec_2_cycles(bcp->congested_period);
+					stat->s_bau_disabled++;
+					for_each_present_cpu(tcpu) {
+						tbcp = &per_cpu(bau_control,
+									tcpu);
+						tbcp->baudisabled = 1;
+					}
+				}
+				spin_unlock(&disable_lock);
+			}
+		}
+	} else
+		stat->s_requestor--; /* don't count this one */
+	if (completion_status == FLUSH_COMPLETE && try > 1)
+		stat->s_retriesok++;
+	else if (completion_status == FLUSH_GIVEUP) {
 		/*
 		 * Cause the caller to do an IPI-style TLB shootdown on
-		 * the cpu's, all of which are still in the mask.
+		 * the target cpu's using the original mask.
 		 */
-		__get_cpu_var(ptcstats).ptc_i++;
-		return flush_mask;
+		stat->s_giveup++;
+		return 1;
 	}
-
 	/*
-	 * Success, so clear the remote cpu's from the mask so we don't
-	 * use the IPI method of shootdown on them.
+	 * Success
 	 */
-	for_each_cpu(bit, flush_mask) {
-		pnode = uv_cpu_to_pnode(bit);
-		if (pnode == this_pnode)
-			continue;
-		cpumask_clear_cpu(bit, flush_mask);
-	}
-	if (!cpumask_empty(flush_mask))
-		return flush_mask;
-	return NULL;
+	return 0;
 }
 
-static DEFINE_PER_CPU(cpumask_var_t, uv_flush_tlb_mask);
-
 /**
  * uv_flush_tlb_others - globally purge translation cache of a virtual
  * address or all TLB's
@@ -322,8 +701,8 @@ static DEFINE_PER_CPU(cpumask_var_t, uv_
  * The caller has derived the cpumask from the mm_struct.  This function
  * is called only if there are bits set in the mask. (e.g. flush_tlb_page())
  *
- * The cpumask is converted into a nodemask of the nodes containing
- * the cpus.
+ * The cpumask is converted into a uvhubmask of the uvhubs containing
+ * those cpus.
  *
  * Note that this function should be called with preemption disabled.
  *
@@ -335,52 +714,100 @@ const struct cpumask *uv_flush_tlb_other
 					  struct mm_struct *mm,
 					  unsigned long va, unsigned int cpu)
 {
-	struct cpumask *flush_mask = __get_cpu_var(uv_flush_tlb_mask);
-	int i;
-	int bit;
-	int pnode;
-	int uv_cpu;
-	int this_pnode;
+	int tcpu;
+	int uvhub;
 	int locals = 0;
+	int remotes = 0;
+	int hubs = 0;
 	struct bau_desc *bau_desc;
+	struct cpumask *flush_mask;
+	struct ptc_stats *stat;
+	struct bau_control *bcp;
+	struct bau_control *tbcp;
 
-	cpumask_andnot(flush_mask, cpumask, cpumask_of(cpu));
+	bcp = &per_cpu(bau_control, cpu);
+	stat = bcp->statp;
 
-	uv_cpu = uv_blade_processor_id();
-	this_pnode = uv_hub_info->pnode;
-	bau_desc = __get_cpu_var(bau_control).descriptor_base;
-	bau_desc += UV_ITEMS_PER_DESCRIPTOR * uv_cpu;
-
-	bau_nodes_clear(&bau_desc->distribution, UV_DISTRIBUTION_SIZE);
-
-	i = 0;
-	for_each_cpu(bit, flush_mask) {
-		pnode = uv_cpu_to_pnode(bit);
-		BUG_ON(pnode > (UV_DISTRIBUTION_SIZE - 1));
-		if (pnode == this_pnode) {
-			locals++;
-			continue;
+	/* bau was disabled due to slow response */
+	if (bcp->baudisabled) {
+		/* the cpu that disabled it must re-enable it */
+		if (bcp->set_bau_off) {
+			if (get_cycles() >= bcp->set_bau_on_time) {
+				stat->s_bau_reenabled++;
+				baudisabled = 0;
+				for_each_present_cpu(tcpu) {
+					tbcp = &per_cpu(bau_control, tcpu);
+					tbcp->baudisabled = 0;
+					tbcp->period_requests = 0;
+					tbcp->period_time = 0;
+				}
+			}
 		}
-		bau_node_set(pnode - uv_partition_base_pnode,
-				&bau_desc->distribution);
-		i++;
+		return cpumask;
 	}
-	if (i == 0) {
-		/*
-		 * no off_node flushing; return status for local node
-		 */
-		if (locals)
-			return flush_mask;
+
+	/*
+	 * Each sending cpu has a per-cpu mask which it fills from the caller's
+	 * cpu mask.  All cpus are converted to uvhubs and copied to the
+	 * activation descriptor.
+	 */
+	flush_mask = (struct cpumask *)per_cpu(uv_flush_tlb_mask, cpu);
+	/* don't actually do a shootdown of the local cpu */
+	cpumask_andnot(flush_mask, cpumask, cpumask_of(cpu));
+	if (cpu_isset(cpu, *cpumask))
+		stat->s_ntargself++;
+
+	bau_desc = bcp->descriptor_base;
+	bau_desc += UV_ITEMS_PER_DESCRIPTOR * bcp->uvhub_cpu;
+	bau_uvhubs_clear(&bau_desc->distribution, UV_DISTRIBUTION_SIZE);
+
+	/* cpu statistics */
+	for_each_cpu(tcpu, flush_mask) {
+		uvhub = uv_cpu_to_blade_id(tcpu);
+		bau_uvhub_set(uvhub, &bau_desc->distribution);
+		if (uvhub == bcp->uvhub)
+			locals++;
 		else
-			return NULL;
+			remotes++;
 	}
-	__get_cpu_var(ptcstats).requestor++;
-	__get_cpu_var(ptcstats).ntargeted += i;
+	if ((locals + remotes) == 0)
+		return NULL;
+	stat->s_requestor++;
+	stat->s_ntargcpu += remotes + locals;
+	stat->s_ntargremotes += remotes;
+	stat->s_ntarglocals += locals;
+	remotes = bau_uvhub_weight(&bau_desc->distribution);
+
+	/* uvhub statistics */
+	hubs = bau_uvhub_weight(&bau_desc->distribution);
+	if (locals) {
+		stat->s_ntarglocaluvhub++;
+		stat->s_ntargremoteuvhub += (hubs - 1);
+	} else
+		stat->s_ntargremoteuvhub += hubs;
+	stat->s_ntarguvhub += hubs;
+	if (hubs >= 16)
+		stat->s_ntarguvhub16++;
+	else if (hubs >= 8)
+		stat->s_ntarguvhub8++;
+	else if (hubs >= 4)
+		stat->s_ntarguvhub4++;
+	else if (hubs >= 2)
+		stat->s_ntarguvhub2++;
+	else
+		stat->s_ntarguvhub1++;
 
 	bau_desc->payload.address = va;
 	bau_desc->payload.sending_cpu = cpu;
 
-	return uv_flush_send_and_wait(uv_cpu, this_pnode, bau_desc, flush_mask);
+	/*
+	 * uv_flush_send_and_wait returns 0 if all cpu's were messaged,
+	 * or 1 if it gave up and the original cpumask should be returned.
+	 */
+	if (!uv_flush_send_and_wait(bau_desc, flush_mask, bcp))
+		return NULL;
+	else
+		return cpumask;
 }
 
 /*
@@ -389,87 +816,70 @@ const struct cpumask *uv_flush_tlb_other
  *
  * We received a broadcast assist message.
  *
- * Interrupts may have been disabled; this interrupt could represent
+ * Interrupts are disabled; this interrupt could represent
  * the receipt of several messages.
  *
- * All cores/threads on this node get this interrupt.
- * The last one to see it does the s/w ack.
+ * All cores/threads on this hub get this interrupt.
+ * The last one to see it does the software ack.
  * (the resource will not be freed until noninterruptable cpus see this
- *  interrupt; hardware will timeout the s/w ack and reply ERROR)
+ *  interrupt; hardware may timeout the s/w ack and reply ERROR)
  */
 void uv_bau_message_interrupt(struct pt_regs *regs)
 {
-	struct bau_payload_queue_entry *va_queue_first;
-	struct bau_payload_queue_entry *va_queue_last;
-	struct bau_payload_queue_entry *msg;
-	struct pt_regs *old_regs = set_irq_regs(regs);
-	cycles_t time1;
-	cycles_t time2;
-	int msg_slot;
-	int sw_ack_slot;
-	int fw;
 	int count = 0;
-	unsigned long local_pnode;
-
-	ack_APIC_irq();
-	exit_idle();
-	irq_enter();
-
-	time1 = get_cycles();
-
-	local_pnode = uv_blade_to_pnode(uv_numa_blade_id());
-
-	va_queue_first = __get_cpu_var(bau_control).va_queue_first;
-	va_queue_last = __get_cpu_var(bau_control).va_queue_last;
+	cycles_t time_start;
+	struct bau_payload_queue_entry *msg;
+	struct bau_control *bcp;
+	struct ptc_stats *stat;
+	struct msg_desc msgdesc;
 
-	msg = __get_cpu_var(bau_control).bau_msg_head;
+	time_start = get_cycles();
+	bcp = &per_cpu(bau_control, smp_processor_id());
+	stat = bcp->statp;
+	msgdesc.va_queue_first = bcp->va_queue_first;
+	msgdesc.va_queue_last = bcp->va_queue_last;
+	msg = bcp->bau_msg_head;
 	while (msg->sw_ack_vector) {
 		count++;
-		fw = msg->sw_ack_vector;
-		msg_slot = msg - va_queue_first;
-		sw_ack_slot = ffs(fw) - 1;
-
-		uv_bau_process_message(msg, msg_slot, sw_ack_slot);
-
+		msgdesc.msg_slot = msg - msgdesc.va_queue_first;
+		msgdesc.sw_ack_slot = ffs(msg->sw_ack_vector) - 1;
+		msgdesc.msg = msg;
+		uv_bau_process_message(&msgdesc, bcp);
 		msg++;
-		if (msg > va_queue_last)
-			msg = va_queue_first;
-		__get_cpu_var(bau_control).bau_msg_head = msg;
+		if (msg > msgdesc.va_queue_last)
+			msg = msgdesc.va_queue_first;
+		bcp->bau_msg_head = msg;
 	}
+	stat->d_time += (get_cycles() - time_start);
 	if (!count)
-		__get_cpu_var(ptcstats).nomsg++;
+		stat->d_nomsg++;
 	else if (count > 1)
-		__get_cpu_var(ptcstats).multmsg++;
-
-	time2 = get_cycles();
-	__get_cpu_var(ptcstats).dflush += (time2 - time1);
-
-	irq_exit();
-	set_irq_regs(old_regs);
+		stat->d_multmsg++;
+	ack_APIC_irq();
 }
 
 /*
  * uv_enable_timeouts
  *
- * Each target blade (i.e. blades that have cpu's) needs to have
+ * Each target uvhub (i.e. a uvhub that has no cpu's) needs to have
  * shootdown message timeouts enabled.  The timeout does not cause
  * an interrupt, but causes an error message to be returned to
  * the sender.
  */
 static void uv_enable_timeouts(void)
 {
-	int blade;
-	int nblades;
+	int uvhub;
+	int nuvhubs;
 	int pnode;
 	unsigned long mmr_image;
 
-	nblades = uv_num_possible_blades();
+	nuvhubs = uv_num_possible_blades();
 
-	for (blade = 0; blade < nblades; blade++) {
-		if (!uv_blade_nr_possible_cpus(blade))
+	for (uvhub = 0; uvhub < nuvhubs; uvhub++) {
+		if (!uv_blade_nr_possible_cpus(uvhub))
 			continue;
 
-		pnode = uv_blade_to_pnode(blade);
+		pnode = uv_blade_to_pnode(uvhub);
 		mmr_image =
 		    uv_read_global_mmr64(pnode, UVH_LB_BAU_MISC_CONTROL);
 		/*
@@ -479,16 +889,16 @@ static void uv_enable_timeouts(void)
 		 * To program the period, the SOFT_ACK_MODE must be off.
 		 */
 		mmr_image &= ~((unsigned long)1 <<
-			       UV_ENABLE_INTD_SOFT_ACK_MODE_SHIFT);
+		    UVH_LB_BAU_MISC_CONTROL_ENABLE_INTD_SOFT_ACK_MODE_SHFT);
 		uv_write_global_mmr64
 		    (pnode, UVH_LB_BAU_MISC_CONTROL, mmr_image);
 		/*
 		 * Set the 4-bit period.
 		 */
 		mmr_image &= ~((unsigned long)0xf <<
-			UV_INTD_SOFT_ACK_TIMEOUT_PERIOD_SHIFT);
+		     UVH_LB_BAU_MISC_CONTROL_INTD_SOFT_ACK_TIMEOUT_PERIOD_SHFT);
 		mmr_image |= (UV_INTD_SOFT_ACK_TIMEOUT_PERIOD <<
-			     UV_INTD_SOFT_ACK_TIMEOUT_PERIOD_SHIFT);
+		     UVH_LB_BAU_MISC_CONTROL_INTD_SOFT_ACK_TIMEOUT_PERIOD_SHFT);
 		uv_write_global_mmr64
 		    (pnode, UVH_LB_BAU_MISC_CONTROL, mmr_image);
 		/*
@@ -497,7 +907,7 @@ static void uv_enable_timeouts(void)
 		 * indicated in bits 2:0 (7 causes all of them to timeout).
 		 */
 		mmr_image |= ((unsigned long)1 <<
-			      UV_ENABLE_INTD_SOFT_ACK_MODE_SHIFT);
+		    UVH_LB_BAU_MISC_CONTROL_ENABLE_INTD_SOFT_ACK_MODE_SHFT);
 		uv_write_global_mmr64
 		    (pnode, UVH_LB_BAU_MISC_CONTROL, mmr_image);
 	}
@@ -522,9 +932,20 @@ static void uv_ptc_seq_stop(struct seq_f
 {
 }
 
+static inline unsigned long long
+microsec_2_cycles(unsigned long microsec)
+{
+	unsigned long ns;
+	unsigned long long cyc;
+
+	ns = microsec * 1000;
+	cyc = (ns << CYC2NS_SCALE_FACTOR)/(per_cpu(cyc2ns, smp_processor_id()));
+	return cyc;
+}
+
 /*
- * Display the statistics thru /proc
- * data points to the cpu number
+ * Display the statistics thru /proc.
+ * 'data' points to the cpu number
  */
 static int uv_ptc_seq_show(struct seq_file *file, void *data)
 {
@@ -535,80 +956,315 @@ static int uv_ptc_seq_show(struct seq_fi
 
 	if (!cpu) {
 		seq_printf(file,
-		"# cpu requestor requestee one all sretry dretry ptc_i ");
+			"# cpu sent stime self locals remotes ncpus localhub ");
+		seq_printf(file,
+			"remotehub numuvhubs numuvhubs16 numuvhubs8 ");
+		seq_printf(file,
+			"numuvhubs4 numuvhubs2 numuvhubs1 dto ");
+		seq_printf(file,
+			"retries rok resetp resett giveup sto bz throt ");
+		seq_printf(file,
+			"sw_ack recv rtime all ");
+		seq_printf(file,
+			"one mult none retry canc nocan reset rcan ");
 		seq_printf(file,
-		"sw_ack sflush dflush sok dnomsg dmult starget\n");
+			"disable enable\n");
 	}
 	if (cpu < num_possible_cpus() && cpu_online(cpu)) {
 		stat = &per_cpu(ptcstats, cpu);
-		seq_printf(file, "cpu %d %ld %ld %ld %ld %ld %ld %ld ",
-			   cpu, stat->requestor,
-			   stat->requestee, stat->onetlb, stat->alltlb,
-			   stat->s_retry, stat->d_retry, stat->ptc_i);
-		seq_printf(file, "%lx %ld %ld %ld %ld %ld %ld\n",
+		/* source side statistics */
+		seq_printf(file,
+			"cpu %d %ld %ld %ld %ld %ld %ld %ld %ld %ld %ld ",
+			   cpu, stat->s_requestor, cycles_2_us(stat->s_time),
+			   stat->s_ntargself, stat->s_ntarglocals,
+			   stat->s_ntargremotes, stat->s_ntargcpu,
+			   stat->s_ntarglocaluvhub, stat->s_ntargremoteuvhub,
+			   stat->s_ntarguvhub, stat->s_ntarguvhub16);
+		seq_printf(file, "%ld %ld %ld %ld %ld ",
+			   stat->s_ntarguvhub8, stat->s_ntarguvhub4,
+			   stat->s_ntarguvhub2, stat->s_ntarguvhub1,
+			   stat->s_dtimeout);
+		seq_printf(file, "%ld %ld %ld %ld %ld %ld %ld %ld ",
+			   stat->s_retry_messages, stat->s_retriesok,
+			   stat->s_resets_plug, stat->s_resets_timeout,
+			   stat->s_giveup, stat->s_stimeout,
+			   stat->s_busy, stat->s_throttles);
+
+		/* destination side statistics */
+		seq_printf(file,
+			   "%lx %ld %ld %ld %ld %ld %ld %ld %ld %ld %ld %ld ",
 			   uv_read_global_mmr64(uv_cpu_to_pnode(cpu),
 					UVH_LB_BAU_INTD_SOFTWARE_ACKNOWLEDGE),
-			   stat->sflush, stat->dflush,
-			   stat->retriesok, stat->nomsg,
-			   stat->multmsg, stat->ntargeted);
+			   stat->d_requestee, cycles_2_us(stat->d_time),
+			   stat->d_alltlb, stat->d_onetlb, stat->d_multmsg,
+			   stat->d_nomsg, stat->d_retries, stat->d_canceled,
+			   stat->d_nocanceled, stat->d_resets,
+			   stat->d_rcanceled);
+		seq_printf(file, "%ld %ld\n",
+			stat->s_bau_disabled, stat->s_bau_reenabled);
 	}
 
 	return 0;
 }
 
 /*
+ * Display the tunables thru debugfs
+ */
+static ssize_t tunables_read(struct file *file, char __user *userbuf,
+						size_t count, loff_t *ppos)
+{
+	char buf[300];
+	int ret;
+
+	ret = snprintf(buf, 300, "%s %s %s\n%d %d %d %d %d %d %d %d %d\n",
+		"max_bau_concurrent plugged_delay plugsb4reset",
+		"timeoutsb4reset ipi_reset_limit complete_threshold",
+		"congested_response_us congested_reps congested_period",
+		max_bau_concurrent, plugged_delay, plugsb4reset,
+		timeoutsb4reset, ipi_reset_limit, complete_threshold,
+		congested_response_us, congested_reps, congested_period);
+
+	return simple_read_from_buffer(userbuf, count, ppos, buf, ret);
+}
+
+/*
+ * -1: resetf the statistics
  *  0: display meaning of the statistics
- * >0: retry limit
  */
 static ssize_t uv_ptc_proc_write(struct file *file, const char __user *user,
 				 size_t count, loff_t *data)
 {
-	long newmode;
+	int cpu;
+	long input_arg;
 	char optstr[64];
+	struct ptc_stats *stat;
 
 	if (count == 0 || count > sizeof(optstr))
 		return -EINVAL;
 	if (copy_from_user(optstr, user, count))
 		return -EFAULT;
 	optstr[count - 1] = '\0';
-	if (strict_strtoul(optstr, 10, &newmode) < 0) {
+	if (strict_strtol(optstr, 10, &input_arg) < 0) {
 		printk(KERN_DEBUG "%s is invalid\n", optstr);
 		return -EINVAL;
 	}
 
-	if (newmode == 0) {
+	if (input_arg == 0) {
 		printk(KERN_DEBUG "# cpu:      cpu number\n");
+		printk(KERN_DEBUG "Sender statistics:\n");
 		printk(KERN_DEBUG
-		"requestor:  times this cpu was the flush requestor\n");
+		"sent:     number of shootdown messages sent\n");
 		printk(KERN_DEBUG
-		"requestee:  times this cpu was requested to flush its TLBs\n");
+		"stime:    time spent sending messages\n");
 		printk(KERN_DEBUG
-		"one:        times requested to flush a single address\n");
+		"numuvhubs: number of hubs targeted with shootdown\n");
 		printk(KERN_DEBUG
-		"all:        times requested to flush all TLB's\n");
+		"numuvhubs16: number times 16 or more hubs targeted\n");
 		printk(KERN_DEBUG
-		"sretry:     number of retries of source-side timeouts\n");
+		"numuvhubs8: number times 8 or more hubs targeted\n");
 		printk(KERN_DEBUG
-		"dretry:     number of retries of destination-side timeouts\n");
+		"numuvhubs4: number times 4 or more hubs targeted\n");
 		printk(KERN_DEBUG
-		"ptc_i:      times UV fell through to IPI-style flushes\n");
+		"numuvhubs2: number times 2 or more hubs targeted\n");
 		printk(KERN_DEBUG
-		"sw_ack:     image of UVH_LB_BAU_INTD_SOFTWARE_ACKNOWLEDGE\n");
+		"numuvhubs1: number times 1 hub targeted\n");
 		printk(KERN_DEBUG
-		"sflush_us:  cycles spent in uv_flush_tlb_others()\n");
+		"numcpus:  number of cpus targeted with shootdown\n");
 		printk(KERN_DEBUG
-		"dflush_us:  cycles spent in handling flush requests\n");
-		printk(KERN_DEBUG "sok:        successes on retry\n");
-		printk(KERN_DEBUG "dnomsg:     interrupts with no message\n");
+		"dto:      number of destination timeouts\n");
 		printk(KERN_DEBUG
-		"dmult:      interrupts with multiple messages\n");
-		printk(KERN_DEBUG "starget:    nodes targeted\n");
-	} else {
-		uv_bau_retry_limit = newmode;
-		printk(KERN_DEBUG "timeout retry limit:%d\n",
-		       uv_bau_retry_limit);
+		"retries:  destination timeout retries sent\n");
+		printk(KERN_DEBUG
+		"rok:   :  destination timeouts successfully retried\n");
+		printk(KERN_DEBUG
+		"resetp:   ipi-style resource resets for plugs\n");
+		printk(KERN_DEBUG
+		"resett:   ipi-style resource resets for timeouts\n");
+		printk(KERN_DEBUG
+		"giveup:   fall-backs to ipi-style shootdowns\n");
+		printk(KERN_DEBUG
+		"sto:      number of source timeouts\n");
+		printk(KERN_DEBUG
+		"bz:       number of stay-busy's\n");
+		printk(KERN_DEBUG
+		"throt:    number times spun in throttle\n");
+		printk(KERN_DEBUG "Destination side statistics:\n");
+		printk(KERN_DEBUG
+		"sw_ack:   image of UVH_LB_BAU_INTD_SOFTWARE_ACKNOWLEDGE\n");
+		printk(KERN_DEBUG
+		"recv:     shootdown messages received\n");
+		printk(KERN_DEBUG
+		"rtime:    time spent processing messages\n");
+		printk(KERN_DEBUG
+		"all:      shootdown all-tlb messages\n");
+		printk(KERN_DEBUG
+		"one:      shootdown one-tlb messages\n");
+		printk(KERN_DEBUG
+		"mult:     interrupts that found multiple messages\n");
+		printk(KERN_DEBUG
+		"none:     interrupts that found no messages\n");
+		printk(KERN_DEBUG
+		"retry:    number of retry messages processed\n");
+		printk(KERN_DEBUG
+		"canc:     number messages canceled by retries\n");
+		printk(KERN_DEBUG
+		"nocan:    number retries that found nothing to cancel\n");
+		printk(KERN_DEBUG
+		"reset:    number of ipi-style reset requests processed\n");
+		printk(KERN_DEBUG
+		"rcan:     number messages canceled by reset requests\n");
+		printk(KERN_DEBUG
+		"disable:  number times use of the BAU was disabled\n");
+		printk(KERN_DEBUG
+		"enable:   number times use of the BAU was re-enabled\n");
+	} else if (input_arg == -1) {
+		for_each_present_cpu(cpu) {
+			stat = &per_cpu(ptcstats, cpu);
+			memset(stat, 0, sizeof(struct ptc_stats));
+		}
+	}
+
+	return count;
+}
+
+static int local_atoi(const char *name)
+{
+	int val = 0;
+
+	for (;; name++) {
+		switch (*name) {
+		case '0' ... '9':
+			val = 10*val+(*name-'0');
+			break;
+		default:
+			return val;
+		}
+	}
+}
+
+/*
+ * set the tunables
+ * 0 values reset them to defaults
+ */
+static ssize_t tunables_write(struct file *file, const char __user *user,
+				 size_t count, loff_t *data)
+{
+	int cpu;
+	int cnt = 0;
+	int val;
+	char *p;
+	char *q;
+	char instr[64];
+	struct bau_control *bcp;
+
+	if (count == 0 || count > sizeof(instr)-1)
+		return -EINVAL;
+	if (copy_from_user(instr, user, count))
+		return -EFAULT;
+
+	instr[count] = '\0';
+	/* count the fields */
+	p = instr + strspn(instr, WHITESPACE);
+	q = p;
+	for (; *p; p = q + strspn(q, WHITESPACE)) {
+		q = p + strcspn(p, WHITESPACE);
+		cnt++;
+		if (q == p)
+			break;
+	}
+	if (cnt != 9) {
+		printk(KERN_INFO "bau tunable error: should be 9 numbers\n");
+		return -EINVAL;
 	}
 
+	p = instr + strspn(instr, WHITESPACE);
+	q = p;
+	for (cnt = 0; *p; p = q + strspn(q, WHITESPACE), cnt++) {
+		q = p + strcspn(p, WHITESPACE);
+		val = local_atoi(p);
+		switch (cnt) {
+		case 0:
+			if (val == 0) {
+				max_bau_concurrent = MAX_BAU_CONCURRENT;
+				max_bau_concurrent_constant =
+							MAX_BAU_CONCURRENT;
+				continue;
+			}
+			bcp = &per_cpu(bau_control, smp_processor_id());
+			if (val < 1 || val > bcp->cpus_in_uvhub) {
+				printk(KERN_DEBUG
+				"Error: BAU max concurrent %d is invalid\n",
+				val);
+				return -EINVAL;
+			}
+			max_bau_concurrent = val;
+			max_bau_concurrent_constant = val;
+			continue;
+		case 1:
+			if (val == 0)
+				plugged_delay = PLUGGED_DELAY;
+			else
+				plugged_delay = val;
+			continue;
+		case 2:
+			if (val == 0)
+				plugsb4reset = PLUGSB4RESET;
+			else
+				plugsb4reset = val;
+			continue;
+		case 3:
+			if (val == 0)
+				timeoutsb4reset = TIMEOUTSB4RESET;
+			else
+				timeoutsb4reset = val;
+			continue;
+		case 4:
+			if (val == 0)
+				ipi_reset_limit = IPI_RESET_LIMIT;
+			else
+				ipi_reset_limit = val;
+			continue;
+		case 5:
+			if (val == 0)
+				complete_threshold = COMPLETE_THRESHOLD;
+			else
+				complete_threshold = val;
+			continue;
+		case 6:
+			if (val == 0)
+				congested_response_us = CONGESTED_RESPONSE_US;
+			else
+				congested_response_us = val;
+			continue;
+		case 7:
+			if (val == 0)
+				congested_reps = CONGESTED_REPS;
+			else
+				congested_reps = val;
+			continue;
+		case 8:
+			if (val == 0)
+				congested_period = CONGESTED_PERIOD;
+			else
+				congested_period = val;
+			continue;
+		}
+		if (q == p)
+			break;
+	}
+	for_each_present_cpu(cpu) {
+		bcp = &per_cpu(bau_control, cpu);
+		bcp->max_bau_concurrent = max_bau_concurrent;
+		bcp->max_bau_concurrent_constant = max_bau_concurrent;
+		bcp->plugged_delay = plugged_delay;
+		bcp->plugsb4reset = plugsb4reset;
+		bcp->timeoutsb4reset = timeoutsb4reset;
+		bcp->ipi_reset_limit = ipi_reset_limit;
+		bcp->complete_threshold = complete_threshold;
+		bcp->congested_response_us = congested_response_us;
+		bcp->congested_reps = congested_reps;
+		bcp->congested_period = congested_period;
+	}
 	return count;
 }
 
@@ -624,6 +1280,11 @@ static int uv_ptc_proc_open(struct inode
 	return seq_open(file, &uv_ptc_seq_ops);
 }
 
+static int tunables_open(struct inode *inode, struct file *file)
+{
+	return 0;
+}
+
 static const struct file_operations proc_uv_ptc_operations = {
 	.open		= uv_ptc_proc_open,
 	.read		= seq_read,
@@ -632,6 +1293,12 @@ static const struct file_operations proc
 	.release	= seq_release,
 };
 
+static const struct file_operations tunables_fops = {
+	.open 		= tunables_open,
+	.read		= tunables_read,
+	.write		= tunables_write,
+};
+
 static int __init uv_ptc_init(void)
 {
 	struct proc_dir_entry *proc_uv_ptc;
@@ -646,83 +1313,48 @@ static int __init uv_ptc_init(void)
 		       UV_PTC_BASENAME);
 		return -EINVAL;
 	}
-	return 0;
-}
-
-/*
- * begin the initialization of the per-blade control structures
- */
-static struct bau_control * __init uv_table_bases_init(int blade, int node)
-{
-	int i;
-	struct bau_msg_status *msp;
-	struct bau_control *bau_tabp;
-
-	bau_tabp =
-	    kmalloc_node(sizeof(struct bau_control), GFP_KERNEL, node);
-	BUG_ON(!bau_tabp);
-
-	bau_tabp->msg_statuses =
-	    kmalloc_node(sizeof(struct bau_msg_status) *
-			 DEST_Q_SIZE, GFP_KERNEL, node);
-	BUG_ON(!bau_tabp->msg_statuses);
-
-	for (i = 0, msp = bau_tabp->msg_statuses; i < DEST_Q_SIZE; i++, msp++)
-		bau_cpubits_clear(&msp->seen_by, (int)
-				  uv_blade_nr_possible_cpus(blade));
-
-	uv_bau_table_bases[blade] = bau_tabp;
 
-	return bau_tabp;
-}
-
-/*
- * finish the initialization of the per-blade control structures
- */
-static void __init
-uv_table_bases_finish(int blade,
-		      struct bau_control *bau_tablesp,
-		      struct bau_desc *adp)
-{
-	struct bau_control *bcp;
-	int cpu;
-
-	for_each_present_cpu(cpu) {
-		if (blade != uv_cpu_to_blade_id(cpu))
-			continue;
-
-		bcp = (struct bau_control *)&per_cpu(bau_control, cpu);
-		bcp->bau_msg_head	= bau_tablesp->va_queue_first;
-		bcp->va_queue_first	= bau_tablesp->va_queue_first;
-		bcp->va_queue_last	= bau_tablesp->va_queue_last;
-		bcp->msg_statuses	= bau_tablesp->msg_statuses;
-		bcp->descriptor_base	= adp;
+	tunables_dir = debugfs_create_dir(UV_BAU_TUNABLES_DIR, NULL);
+	if (!tunables_dir) {
+		printk(KERN_ERR "unable to create debugfs directory %s\n",
+		       UV_BAU_TUNABLES_DIR);
+		return -EINVAL;
+	}
+	tunables_file = debugfs_create_file(UV_BAU_TUNABLES_FILE, 0600,
+			tunables_dir, NULL, &tunables_fops);
+	if (!tunables_file) {
+		printk(KERN_ERR "unable to create debugfs file %s\n",
+		       UV_BAU_TUNABLES_FILE);
+		return -EINVAL;
 	}
+	return 0;
 }
 
 /*
  * initialize the sending side's sending buffers
  */
-static struct bau_desc * __init
+static void
 uv_activation_descriptor_init(int node, int pnode)
 {
 	int i;
+	int cpu;
 	unsigned long pa;
 	unsigned long m;
 	unsigned long n;
-	struct bau_desc *adp;
-	struct bau_desc *ad2;
+	struct bau_desc *bau_desc;
+	struct bau_desc *bd2;
+	struct bau_control *bcp;
 
 	/*
 	 * each bau_desc is 64 bytes; there are 8 (UV_ITEMS_PER_DESCRIPTOR)
-	 * per cpu; and up to 32 (UV_ADP_SIZE) cpu's per blade
+	 * per cpu; and up to 32 (UV_ADP_SIZE) cpu's per uvhub
 	 */
-	adp = (struct bau_desc *)kmalloc_node(sizeof(struct bau_desc)*
+	bau_desc = (struct bau_desc *)kmalloc_node(sizeof(struct bau_desc)*
 		UV_ADP_SIZE*UV_ITEMS_PER_DESCRIPTOR, GFP_KERNEL, node);
-	BUG_ON(!adp);
+	BUG_ON(!bau_desc);
 
-	pa = uv_gpa(adp); /* need the real nasid*/
-	n = uv_gpa_to_pnode(pa);
+	pa = uv_gpa(bau_desc); /* need the real nasid*/
+	n = pa >> uv_nshift;
 	m = pa & uv_mmask;
 
 	uv_write_global_mmr64(pnode, UVH_LB_BAU_SB_DESCRIPTOR_BASE,
@@ -731,96 +1363,243 @@ uv_activation_descriptor_init(int node, 
 	/*
 	 * initializing all 8 (UV_ITEMS_PER_DESCRIPTOR) descriptors for each
 	 * cpu even though we only use the first one; one descriptor can
-	 * describe a broadcast to 256 nodes.
+	 * describe a broadcast to 256 uv hubs.
 	 */
-	for (i = 0, ad2 = adp; i < (UV_ADP_SIZE*UV_ITEMS_PER_DESCRIPTOR);
-		i++, ad2++) {
-		memset(ad2, 0, sizeof(struct bau_desc));
-		ad2->header.sw_ack_flag = 1;
+	for (i = 0, bd2 = bau_desc; i < (UV_ADP_SIZE*UV_ITEMS_PER_DESCRIPTOR);
+		i++, bd2++) {
+		memset(bd2, 0, sizeof(struct bau_desc));
+		bd2->header.sw_ack_flag = 1;
 		/*
-		 * base_dest_nodeid is the first node in the partition, so
-		 * the bit map will indicate partition-relative node numbers.
-		 * note that base_dest_nodeid is actually a nasid.
+		 * base_dest_nodeid is the nasid (pnode<<1) of the first uvhub
+		 * in the partition. The bit map will indicate uvhub numbers,
+		 * which are 0-N in a partition. Pnodes are unique system-wide.
 		 */
-		ad2->header.base_dest_nodeid = uv_partition_base_pnode << 1;
-		ad2->header.dest_subnodeid = 0x10; /* the LB */
-		ad2->header.command = UV_NET_ENDPOINT_INTD;
-		ad2->header.int_both = 1;
+		bd2->header.base_dest_nodeid = uv_partition_base_pnode << 1;
+		bd2->header.dest_subnodeid = 0x10; /* the LB */
+		bd2->header.command = UV_NET_ENDPOINT_INTD;
+		bd2->header.int_both = 1;
 		/*
 		 * all others need to be set to zero:
 		 *   fairness chaining multilevel count replied_to
 		 */
 	}
-	return adp;
+	for_each_present_cpu(cpu) {
+		if (pnode != uv_blade_to_pnode(uv_cpu_to_blade_id(cpu)))
+			continue;
+		bcp = &per_cpu(bau_control, cpu);
+		bcp->descriptor_base = bau_desc;
+	}
 }
 
 /*
  * initialize the destination side's receiving buffers
+ * entered for each uvhub in the partition
+ * - node is first node (kernel memory notion) on the uvhub
+ * - pnode is the uvhub's physical identifier
  */
-static struct bau_payload_queue_entry * __init
-uv_payload_queue_init(int node, int pnode, struct bau_control *bau_tablesp)
+static void
+uv_payload_queue_init(int node, int pnode)
 {
-	struct bau_payload_queue_entry *pqp;
-	unsigned long pa;
 	int pn;
+	int cpu;
 	char *cp;
+	unsigned long pa;
+	struct bau_payload_queue_entry *pqp;
+	struct bau_payload_queue_entry *pqp_malloc;
+	struct bau_control *bcp;
 
 	pqp = (struct bau_payload_queue_entry *) kmalloc_node(
 		(DEST_Q_SIZE + 1) * sizeof(struct bau_payload_queue_entry),
 		GFP_KERNEL, node);
 	BUG_ON(!pqp);
+	pqp_malloc = pqp;
 
 	cp = (char *)pqp + 31;
 	pqp = (struct bau_payload_queue_entry *)(((unsigned long)cp >> 5) << 5);
-	bau_tablesp->va_queue_first = pqp;
+
+	for_each_present_cpu(cpu) {
+		if (pnode != uv_cpu_to_pnode(cpu))
+			continue;
+		/* for every cpu on this pnode: */
+		bcp = &per_cpu(bau_control, cpu);
+		bcp->va_queue_first = pqp;
+		bcp->bau_msg_head = pqp;
+		bcp->va_queue_last = pqp + (DEST_Q_SIZE - 1);
+	}
 	/*
 	 * need the pnode of where the memory was really allocated
 	 */
 	pa = uv_gpa(pqp);
-	pn = uv_gpa_to_pnode(pa);
+	pn = pa >> uv_nshift;
 	uv_write_global_mmr64(pnode,
 			      UVH_LB_BAU_INTD_PAYLOAD_QUEUE_FIRST,
 			      ((unsigned long)pn << UV_PAYLOADQ_PNODE_SHIFT) |
 			      uv_physnodeaddr(pqp));
 	uv_write_global_mmr64(pnode, UVH_LB_BAU_INTD_PAYLOAD_QUEUE_TAIL,
 			      uv_physnodeaddr(pqp));
-	bau_tablesp->va_queue_last = pqp + (DEST_Q_SIZE - 1);
 	uv_write_global_mmr64(pnode, UVH_LB_BAU_INTD_PAYLOAD_QUEUE_LAST,
 			      (unsigned long)
-			      uv_physnodeaddr(bau_tablesp->va_queue_last));
+			      uv_physnodeaddr(pqp + (DEST_Q_SIZE - 1)));
+	/* in effect, all msg_type's are set to MSG_NOOP */
 	memset(pqp, 0, sizeof(struct bau_payload_queue_entry) * DEST_Q_SIZE);
-
-	return pqp;
 }
 
 /*
- * Initialization of each UV blade's structures
+ * Initialization of each UV hub's structures
  */
-static int __init uv_init_blade(int blade)
+static void __init uv_init_uvhub(int uvhub, int vector)
 {
 	int node;
 	int pnode;
-	unsigned long pa;
 	unsigned long apicid;
-	struct bau_desc *adp;
-	struct bau_payload_queue_entry *pqp;
-	struct bau_control *bau_tablesp;
 
-	node = blade_to_first_node(blade);
-	bau_tablesp = uv_table_bases_init(blade, node);
-	pnode = uv_blade_to_pnode(blade);
-	adp = uv_activation_descriptor_init(node, pnode);
-	pqp = uv_payload_queue_init(node, pnode, bau_tablesp);
-	uv_table_bases_finish(blade, bau_tablesp, adp);
+	node = uvhub_to_first_node(uvhub);
+	pnode = uv_blade_to_pnode(uvhub);
+	uv_activation_descriptor_init(node, pnode);
+	uv_payload_queue_init(node, pnode);
 	/*
 	 * the below initialization can't be in firmware because the
 	 * messaging IRQ will be determined by the OS
 	 */
-	apicid = blade_to_first_apicid(blade);
-	pa = uv_read_global_mmr64(pnode, UVH_BAU_DATA_CONFIG);
+	apicid = uvhub_to_first_apicid(uvhub);
 	uv_write_global_mmr64(pnode, UVH_BAU_DATA_CONFIG,
-				      ((apicid << 32) | UV_BAU_MESSAGE));
-	return 0;
+				      ((apicid << 32) | vector));
+}
+
+/*
+ * We will set BAU_MISC_CONTROL with a timeout period.
+ * But the BIOS has set UVH_AGING_PRESCALE_SEL and UVH_TRANSACTION_TIMEOUT.
+ * So the destination timeout period has be be calculated from them.
+ */
+static int
+calculate_destination_timeout(void)
+{
+	unsigned long mmr_image;
+	int mult1;
+	int mult2;
+	int index;
+	int base;
+	int ret;
+	unsigned long ts_ns;
+
+	mult1 = UV_INTD_SOFT_ACK_TIMEOUT_PERIOD & BAU_MISC_CONTROL_MULT_MASK;
+	mmr_image = uv_read_local_mmr(UVH_AGING_PRESCALE_SEL);
+	index = (mmr_image >> BAU_URGENCY_7_SHIFT) & BAU_URGENCY_7_MASK;
+	mmr_image = uv_read_local_mmr(UVH_TRANSACTION_TIMEOUT);
+	mult2 = (mmr_image >> BAU_TRANS_SHIFT) & BAU_TRANS_MASK;
+	base = timeout_base_ns[index];
+	ts_ns = base * mult1 * mult2;
+	ret = ts_ns / 1000;
+	return ret;
+}
+
+/*
+ * initialize the bau_control structure for each cpu
+ */
+static void uv_init_per_cpu(int nuvhubs)
+{
+	int i;
+	int cpu;
+	int pnode;
+	int uvhub;
+	short socket = 0;
+	unsigned short socket_mask;
+	unsigned int uvhub_mask;
+	struct bau_control *bcp;
+	struct uvhub_desc *bdp;
+	struct socket_desc *sdp;
+	struct bau_control *hmaster = NULL;
+	struct bau_control *smaster = NULL;
+	struct socket_desc {
+		short num_cpus;
+		short cpu_number[16];
+	};
+	struct uvhub_desc {
+		unsigned short socket_mask;
+		short num_cpus;
+		short uvhub;
+		short pnode;
+		struct socket_desc socket[2];
+	};
+	struct uvhub_desc *uvhub_descs;
+
+	timeout_us = calculate_destination_timeout();
+
+	uvhub_descs = (struct uvhub_desc *)
+		kmalloc(nuvhubs * sizeof(struct uvhub_desc), GFP_KERNEL);
+	memset(uvhub_descs, 0, nuvhubs * sizeof(struct uvhub_desc));
+	for_each_present_cpu(cpu) {
+		bcp = &per_cpu(bau_control, cpu);
+		memset(bcp, 0, sizeof(struct bau_control));
+		pnode = uv_cpu_hub_info(cpu)->pnode;
+		uvhub = uv_cpu_hub_info(cpu)->numa_blade_id;
+		uvhub_mask |= (1 << uvhub);
+		bdp = &uvhub_descs[uvhub];
+		bdp->num_cpus++;
+		bdp->uvhub = uvhub;
+		bdp->pnode = pnode;
+		/* kludge: 'assuming' one node per socket, and assuming that
+		   disabling a socket just leaves a gap in node numbers */
+		socket = (cpu_to_node(cpu) & 1);;
+		bdp->socket_mask |= (1 << socket);
+		sdp = &bdp->socket[socket];
+		sdp->cpu_number[sdp->num_cpus] = cpu;
+		sdp->num_cpus++;
+	}
+	uvhub = 0;
+	while (uvhub_mask) {
+		if (!(uvhub_mask & 1))
+			goto nexthub;
+		bdp = &uvhub_descs[uvhub];
+		socket_mask = bdp->socket_mask;
+		socket = 0;
+		while (socket_mask) {
+			if (!(socket_mask & 1))
+				goto nextsocket;
+			sdp = &bdp->socket[socket];
+			for (i = 0; i < sdp->num_cpus; i++) {
+				cpu = sdp->cpu_number[i];
+				bcp = &per_cpu(bau_control, cpu);
+				bcp->cpu = cpu;
+				if (i == 0) {
+					smaster = bcp;
+					if (socket == 0)
+						hmaster = bcp;
+				}
+				bcp->cpus_in_uvhub = bdp->num_cpus;
+				bcp->cpus_in_socket = sdp->num_cpus;
+				bcp->socket_master = smaster;
+				bcp->uvhub = bdp->uvhub;
+				bcp->uvhub_master = hmaster;
+				bcp->uvhub_cpu = uv_cpu_hub_info(cpu)->
+						blade_processor_id;
+			}
+nextsocket:
+			socket++;
+			socket_mask = (socket_mask >> 1);
+		}
+nexthub:
+		uvhub++;
+		uvhub_mask = (uvhub_mask >> 1);
+	}
+	kfree(uvhub_descs);
+	for_each_present_cpu(cpu) {
+		bcp = &per_cpu(bau_control, cpu);
+		bcp->baudisabled = 0;
+		bcp->statp = &per_cpu(ptcstats, cpu);
+		/* time interval to catch a hardware stay-busy bug */
+		bcp->timeout_interval = microsec_2_cycles(2*timeout_us);
+		bcp->max_bau_concurrent = max_bau_concurrent;
+		bcp->max_bau_concurrent_constant = max_bau_concurrent;
+		bcp->plugged_delay = plugged_delay;
+		bcp->plugsb4reset = plugsb4reset;
+		bcp->timeoutsb4reset = timeoutsb4reset;
+		bcp->ipi_reset_limit = ipi_reset_limit;
+		bcp->complete_threshold = complete_threshold;
+		bcp->congested_response_us = congested_response_us;
+		bcp->congested_reps = congested_reps;
+		bcp->congested_period = congested_period;
+	}
 }
 
 /*
@@ -828,38 +1607,55 @@ static int __init uv_init_blade(int blad
  */
 static int __init uv_bau_init(void)
 {
-	int blade;
-	int nblades;
+	int uvhub;
+	int pnode;
+	int nuvhubs;
 	int cur_cpu;
+	int vector;
+	unsigned long mmr;
 
 	if (!is_uv_system())
 		return 0;
 
+	if (nobau)
+		return 0;
+
 	for_each_possible_cpu(cur_cpu)
 		zalloc_cpumask_var_node(&per_cpu(uv_flush_tlb_mask, cur_cpu),
 				       GFP_KERNEL, cpu_to_node(cur_cpu));
 
-	uv_bau_retry_limit = 1;
+	uv_nshift = uv_hub_info->m_val;
 	uv_mmask = (1UL << uv_hub_info->m_val) - 1;
-	nblades = uv_num_possible_blades();
+	nuvhubs = uv_num_possible_blades();
+	spin_lock_init(&disable_lock);
+	congested_cycles = microsec_2_cycles(congested_response_us);
 
-	uv_bau_table_bases = (struct bau_control **)
-	    kmalloc(nblades * sizeof(struct bau_control *), GFP_KERNEL);
-	BUG_ON(!uv_bau_table_bases);
+	uv_init_per_cpu(nuvhubs);
 
 	uv_partition_base_pnode = 0x7fffffff;
-	for (blade = 0; blade < nblades; blade++)
-		if (uv_blade_nr_possible_cpus(blade) &&
-			(uv_blade_to_pnode(blade) < uv_partition_base_pnode))
-			uv_partition_base_pnode = uv_blade_to_pnode(blade);
-	for (blade = 0; blade < nblades; blade++)
-		if (uv_blade_nr_possible_cpus(blade))
-			uv_init_blade(blade);
+	for (uvhub = 0; uvhub < nuvhubs; uvhub++)
+		if (uv_blade_nr_possible_cpus(uvhub) &&
+			(uv_blade_to_pnode(uvhub) < uv_partition_base_pnode))
+			uv_partition_base_pnode = uv_blade_to_pnode(uvhub);
+
+	vector = UV_BAU_MESSAGE;
+	for_each_possible_blade(uvhub)
+		if (uv_blade_nr_possible_cpus(uvhub))
+			uv_init_uvhub(uvhub, vector);
 
-	alloc_intr_gate(UV_BAU_MESSAGE, uv_bau_message_intr1);
 	uv_enable_timeouts();
+	alloc_intr_gate(vector, uv_bau_message_intr1);
+
+	for_each_possible_blade(uvhub) {
+		pnode = uv_blade_to_pnode(uvhub);
+		/* INIT the bau */
+		uv_write_global_mmr64(pnode, UVH_LB_BAU_SB_ACTIVATION_CONTROL,
+				      ((unsigned long)1 << 63));
+		mmr = 1; /* should be 1 to broadcast to both sockets */
+		uv_write_global_mmr64(pnode, UVH_BAU_DATA_BROADCAST, mmr);
+	}
 
 	return 0;
 }
-__initcall(uv_bau_init);
-__initcall(uv_ptc_init);
+core_initcall(uv_bau_init);
+fs_initcall(uv_ptc_init);
--
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