This patch makes some basic statistics for RCU available in /proc/rcu.
It is a trimmed down version of the earler rcu_stats patch in -mm kernels.
I removed all the RCU implementation dependent stats (mostly needed for
debugging) and retained only the part that was very generic in
nature - # of RCU requests and # of actual RCU updates for each
CPU. This will allow us to monitor the health of the RCU
subsystem and such things have been extremely useful for me to
investigate problems.
[dipankar@llm04 dipankar]$ cat /proc/rcu
CPU : 0
RCU requests : 0
RCU updates : 0
CPU : 1
RCU requests : 0
RCU updates : 0
CPU : 2
RCU requests : 0
RCU updates : 0
CPU : 3
RCU requests : 0
RCU updates : 0
Thanks
-- Dipankar Sarma <dipankar@in.ibm.com> http://lse.sourceforge.net Linux Technology Center, IBM Software Lab, Bangalore, India.diff -urN linux-2.5.46-base/Documentation/filesystems/proc.txt linux-2.5.46-misc/Documentation/filesystems/proc.txt --- linux-2.5.46-base/Documentation/filesystems/proc.txt Tue Nov 5 21:58:17 2002 +++ linux-2.5.46-misc/Documentation/filesystems/proc.txt Wed Nov 6 21:07:55 2002 @@ -222,6 +222,7 @@ partitions Table of partitions known to the system pci Depreciated info of PCI bus (new way -> /proc/bus/pci/, decoupled by lspci (2.4) + rcu Read-Copy Update information (2.5) rtc Real time clock scsi SCSI info (see text) slabinfo Slab pool info @@ -346,6 +347,9 @@ ZONE_DMA, 4 chunks of 2^1*PAGE_SIZE in ZONE_DMA, 101 chunks of 2^4*PAGE_SIZE availble in ZONE_NORMAL, etc... +The rcu file gives information about Read-Copy Update synchronization +primitive. It indicates the number for RCU requests and actual +updates for every CPU. 1.3 IDE devices in /proc/ide ---------------------------- diff -urN linux-2.5.46-base/fs/proc/proc_misc.c linux-2.5.46-misc/fs/proc/proc_misc.c --- linux-2.5.46-base/fs/proc/proc_misc.c Tue Nov 5 21:58:27 2002 +++ linux-2.5.46-misc/fs/proc/proc_misc.c Tue Nov 5 23:30:40 2002 @@ -253,6 +253,18 @@ .release = seq_release, }; +extern struct seq_operations rcu_op; +static int rcu_open(struct inode *inode, struct file *file) +{ + return seq_open(file, &rcu_op); +} +static struct file_operations proc_rcu_operations = { + .open = rcu_open, + .read = seq_read, + .llseek = seq_lseek, + .release = seq_release, +}; + extern struct seq_operations vmstat_op; static int vmstat_open(struct inode *inode, struct file *file) { @@ -627,6 +639,7 @@ if (entry) entry->proc_fops = &proc_kmsg_operations; create_seq_entry("cpuinfo", 0, &proc_cpuinfo_operations); + create_seq_entry("rcu", 0, &proc_rcu_operations); create_seq_entry("partitions", 0, &proc_partitions_operations); #if !defined(CONFIG_ARCH_S390) create_seq_entry("interrupts", 0, &proc_interrupts_operations); diff -urN linux-2.5.46-base/include/linux/rcupdate.h linux-2.5.46-misc/include/linux/rcupdate.h --- linux-2.5.46-base/include/linux/rcupdate.h Fri Nov 1 13:10:34 2002 +++ linux-2.5.46-misc/include/linux/rcupdate.h Wed Nov 6 23:36:17 2002 @@ -95,6 +95,8 @@ long batch; /* Batch # for current RCU batch */ struct list_head nxtlist; struct list_head curlist; + long nr_rcureqs; + long nr_rcupdates; }; DECLARE_PER_CPU(struct rcu_data, rcu_data); @@ -105,6 +107,8 @@ #define RCU_batch(cpu) (per_cpu(rcu_data, (cpu)).batch) #define RCU_nxtlist(cpu) (per_cpu(rcu_data, (cpu)).nxtlist) #define RCU_curlist(cpu) (per_cpu(rcu_data, (cpu)).curlist) +#define RCU_nr_rcureqs(cpu) (per_cpu(rcu_data, (cpu)).nr_rcureqs) +#define RCU_nr_rcupdates(cpu) (per_cpu(rcu_data, (cpu)).nr_rcupdates) #define RCU_QSCTR_INVALID 0 diff -urN linux-2.5.46-base/kernel/rcupdate.c linux-2.5.46-misc/kernel/rcupdate.c --- linux-2.5.46-base/kernel/rcupdate.c Fri Nov 1 13:10:34 2002 +++ linux-2.5.46-misc/kernel/rcupdate.c Wed Nov 6 23:36:39 2002 @@ -41,6 +41,7 @@ #include <linux/module.h> #include <linux/completion.h> #include <linux/percpu.h> +#include <linux/seq_file.h> #include <linux/notifier.h> #include <linux/rcupdate.h> @@ -75,6 +76,7 @@ local_irq_save(flags); cpu = smp_processor_id(); list_add_tail(&head->list, &RCU_nxtlist(cpu)); + RCU_nr_rcureqs(cpu)++; local_irq_restore(flags); } @@ -82,7 +84,7 @@ * Invoke the completed RCU callbacks. They are expected to be in * a per-cpu list. */ -static void rcu_do_batch(struct list_head *list) +static void rcu_do_batch(int cpu, struct list_head *list) { struct list_head *entry; struct rcu_head *head; @@ -92,6 +94,7 @@ list_del(entry); head = list_entry(entry, struct rcu_head, list); head->func(head->arg); + RCU_nr_rcupdates(cpu)++; } } @@ -187,7 +190,7 @@ } rcu_check_quiescent_state(); if (!list_empty(&list)) - rcu_do_batch(&list); + rcu_do_batch(cpu, &list); } void rcu_check_callbacks(int cpu, int user) @@ -266,3 +269,44 @@ EXPORT_SYMBOL(call_rcu); EXPORT_SYMBOL(synchronize_kernel); + +#ifdef CONFIG_PROC_FS + +static void *rcu_start(struct seq_file *m, loff_t *pos) +{ + static int cpu; + cpu = *pos; + return *pos < NR_CPUS ? &cpu : NULL; +} + +static void *rcu_next(struct seq_file *m, void *v, loff_t *pos) +{ + ++*pos; + return rcu_start(m, pos); +} + +static void rcu_stop(struct seq_file *m, void *v) +{ +} + +static int show_rcu(struct seq_file *m, void *v) +{ + int cpu = *(int *)v; + + if (!cpu_online(cpu)) + return 0; + seq_printf(m, "CPU : %d\n", cpu); + seq_printf(m, "RCU requests : %ld\n", RCU_nr_rcureqs(cpu)); + seq_printf(m, "RCU updates : %ld\n\n", RCU_nr_rcupdates(cpu)); + return 0; +} + +struct seq_operations rcu_op = { + .start = rcu_start, + .next = rcu_next, + .stop = rcu_stop, + .show = show_rcu, +}; + +#endif + - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
This archive was generated by hypermail 2b29 : Thu Nov 07 2002 - 22:00:47 EST