[RFC][PATCH 3/3] perf/Power7: Export DCACHE_SRC field to userspace
From: Sukadev Bhattiprolu
Date: Wed Jun 26 2013 - 03:43:32 EST
From: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx>
Date: Tue, 25 Jun 2013 17:12:02 -0700
Subject: [RFC][PATCH 3/3] perf/Power7: Export DCACHE_SRC field to userspace
On Power7, the DCACHE_SRC field (bits 9..12), in the MMCRA register
identify the source from which a data-cache-miss for a marked instruction
was satisified.
Map this source to the architecture-neutral memory hierarchy levels
and add to the sample record so the source information is available to
user space.
Arch-neutral levels Power7 levels
-----------------------------------------------------------------------
local LVL_L2 local (same core) L2 (FROM_L2)
local LVL_L3 local (same core) L3 (FROM_L3)
1-hop XLVL_REM_L2_CCE1* different core on same chip (FROM_L2.1)
1-hop XLVL_REM_L3_CCE1* different core on same chip (FROM_L3.1)
2-hops LVL_REM_CCE2 remote (different chip, same node) (FROM_RL2L3)
3-hops XLVL_REM_CCE3* distant (different node) (FROM_DL2L3)
1-hop LVL_REM_RAM1 unused
2-hops LVL_REM_RAM2 remote (different chip, same node) (FROM_RMEM)
3-hops XLVL_REM_RAM3* distant (different node) (FROM_DMEM)
As shown above, Power7 supports one extra level in the cache-hierarchy (i.e
total of 3-hops). To maintain consistency in terminology (i.e 2-hops = remote,
3-hops = distant), we propose leaving the REM_RAM1 unused in Power7 and adding
another level, REM_CCE3 and REM_RAM3.
Further, in the REM_CCE1 case, Power7 can also identify if the data came from
the L2 or L3 cache of another core on the same chip. To describe this add the
levels:
PERF_MEM_XLVL_REM_L2_CCE1
PERF_MEM_XLVL_REM_L3_CCE1
Finally, in the REM_CCE1 and REM_CCE2 cases, Power7 also indicates whether
the entry found in the remote cache was modified (dirty). So we add a new
state
PERF_MEM_XLVL_CCE_DIRTY
Testing:
memarray is a simple test case that creates a large 2D array and accesses
elements in the array in strides of varying length. Using the perf event
PM_MRK_LD_MISS_L1_CYC (r4003e) with memarrary, we get samples like:
4989704543010 0x1470 [0x38]: PERF_RECORD_SAMPLE(IP, 1): 10816/10816:
0xc0000000001ef514 period: 1 addr: 0xc0000001e64538d8
. data_src: 0x400
... thread: memarray:10816
...... dso: [kernel.kallsyms]
4990265034542 0x9a00 [0x38]: PERF_RECORD_SAMPLE(IP, 3): 10816/10816:
0x54696c period: 2996 addr: 0x8000000064a3001a
. data_src: 0x800
... thread: memarray:10816
...... dso: [hypervisor]
4990505534586 0xd2e0 [0x38]: PERF_RECORD_SAMPLE(IP, 1): 10816/10816:
0xc00000000019bb28 period: 2979 addr: 0xc0000001fffaba40
. data_src: 0x200000000000
... thread: memarray:10816
...... dso: [kernel.kallsyms]
where, the 'data_src' values indicate:
0x400 PERF_MEM_LVL_L2, FROM_L2
0x800 PERF_MEM_LVL_L3, FROM_L3
0x200000000000 PERF_MEM_XLVL_REM_L2_CCE1 FROM_L2.1_SHR
Signed-off-by: Sukadev Bhattiprolu <sukadev@xxxxxxxxxxxxxxxxxx>
---
Changelog[v2]:
[Stephane Eranian] Define new levels rather than ORing the L2 and L3
with REM_CCE1 and REM_CCE2.
[Stephane Eranian] allocate a bit PERF_MEM_XLVL_NA for architectures
that don't use the ->mem_xlvl field.
Insert the TLB patch ahead so the new TLB bits are contigous with
existing TLB bits.
arch/powerpc/perf/power7-pmu.c | 44 +++++++++++++++++++++++++++++++++++++++
include/uapi/linux/perf_event.h | 13 ++++++++++-
2 files changed, 56 insertions(+), 1 deletions(-)
diff --git a/arch/powerpc/perf/power7-pmu.c b/arch/powerpc/perf/power7-pmu.c
index c1cac96..8cb4cbc 100644
--- a/arch/powerpc/perf/power7-pmu.c
+++ b/arch/powerpc/perf/power7-pmu.c
@@ -209,6 +209,10 @@ static int power7_get_alternatives(u64 event, unsigned int flags, u64 alt[])
return nalt;
}
+#define POWER7_MMCRA_DCACHE_MISS (0x1LL << 55)
+#define POWER7_MMCRA_DCACHE_SRC_SHIFT 51
+#define POWER7_MMCRA_DCACHE_SRC_MASK (0xFLL << POWER7_MMCRA_DCACHE_SRC_SHIFT)
+
#define POWER7_MMCRA_MDTLB_MISS (0x1LL << 50)
#define POWER7_MMCRA_MDTLB_SRC_SHIFT 46
#define POWER7_MMCRA_MDTLB_SRC_MASK (0xFLL << POWER7_MMCRA_MDTLB_SRC_SHIFT)
@@ -231,6 +235,7 @@ static int power7_get_alternatives(u64 event, unsigned int flags, u64 alt[])
*/
#define P(a, b) PERF_MEM_S(a, b)
#define TD(a, b) (P(TLB, CCE_DIRTY) | P(a, b))
+#define XD(a, b) (P(XLVL, CCE_DIRTY) | P(a, b))
static u64 mdtlb_src_map[] = {
P(TLB, L2), /* 00: FROM_L2 */
@@ -258,6 +263,37 @@ static u64 mdtlb_src_map[] = {
P(TLB, NA), /* 15: Reserved */
};
+/*
+ * Similar to mdtlb_src_map[] table above, use dcache_src_map[] to map
+ * the Power7 DCACHE_SRC field (bits 9..12) in MMCRA register to the
+ * Linux memory hierarchy levels.
+ */
+static u64 dcache_src_map[] = {
+ P(LVL, L2), /* 00: FROM_L2 */
+ P(LVL, L3), /* 01: FROM_L3 */
+
+ P(LVL, NA), /* 02: Reserved */
+ P(LVL, NA), /* 03: Reserved */
+
+ P(XLVL, REM_L2_CCE1), /* 04: FROM_L2.1_SHR */
+ XD(XLVL, REM_L2_CCE1), /* 05: FROM_L2.1_MOD */
+
+ P(XLVL, REM_L3_CCE1), /* 06: FROM_L3.1_SHR */
+ XD(XLVL, REM_L3_CCE1), /* 07: FROM_L3.1_MOD */
+
+ P(LVL, REM_CCE2), /* 08: FROM_RL2L3_SHR */
+ XD(LVL, REM_CCE2), /* 09: FROM_RL2L3_MOD */
+
+ P(XLVL, REM_CCE3), /* 10: FROM_DL2L3_SHR */
+ XD(XLVL, REM_CCE3), /* 11: FROM_DL2L3_MOD */
+
+ P(LVL, LOC_RAM), /* 12: FROM_LMEM */
+ P(LVL, REM_RAM2), /* 13: FROM_RMEM */
+ P(XLVL, REM_RAM3), /* 14: FROM_DMEM */
+
+ P(LVL, NA), /* 15: Reserved */
+};
+
static void power7_get_mem_data_src(union perf_mem_data_src *dsrc,
struct pt_regs *regs)
{
@@ -270,6 +306,14 @@ static void power7_get_mem_data_src(union perf_mem_data_src *dsrc,
dsrc->val |= mdtlb_src_map[idx];
}
+
+ if (mmcra & POWER7_MMCRA_DCACHE_MISS) {
+ idx = mmcra & POWER7_MMCRA_DCACHE_SRC_MASK;
+ idx >>= POWER7_MMCRA_DCACHE_SRC_SHIFT;
+
+ dsrc->val |= dcache_src_map[idx];
+ }
+
}
/*
diff --git a/include/uapi/linux/perf_event.h b/include/uapi/linux/perf_event.h
index 815ee12..149b33d 100644
--- a/include/uapi/linux/perf_event.h
+++ b/include/uapi/linux/perf_event.h
@@ -627,7 +627,8 @@ union perf_mem_data_src {
mem_snoop:5, /* snoop mode */
mem_lock:2, /* lock instr */
mem_dtlb:17, /* tlb access */
- mem_rsvd:21;
+ mem_xlvl:6, /* memory hierarchy levels contd */
+ mem_rsvd:15;
};
};
@@ -655,6 +656,7 @@ union perf_mem_data_src {
#define PERF_MEM_LVL_REM_CCE2 0x800 /* Remote Cache (2 hops) */
#define PERF_MEM_LVL_IO 0x1000 /* I/O memory */
#define PERF_MEM_LVL_UNC 0x2000 /* Uncached memory */
+/* memory hierarchy levels continued/extended below */
/* snoop mode */
#define PERF_MEM_SNOOP_SHIFT 19
@@ -689,6 +691,15 @@ union perf_mem_data_src {
#define PERF_MEM_TLB_REM_RAM3 0x8000 /* Remote DRAM (3 hops) */
#define PERF_MEM_TLB_CCE_DIRTY 0x10000 /* Remote cache entry hit, but dirty */
+/* Extended levels i.e. continuation of PERF_MEM_LVL* values above. */
+#define PERF_MEM_XLVL_SHIFT 43
+#define PERF_MEM_XLVL_NA 0x01 /* not available */
+#define PERF_MEM_XLVL_CCE_DIRTY 0x02 /* cache entry hit, was dirty */
+#define PERF_MEM_XLVL_REM_L2_CCE1 0x04 /* Remote L2-cache (1 hop) */
+#define PERF_MEM_XLVL_REM_L3_CCE1 0x08 /* Remote L3-cache (1 hop) */
+#define PERF_MEM_XLVL_REM_CCE3 0x10 /* Remote cache (3 hops) */
+#define PERF_MEM_XLVL_REM_RAM3 0x20 /* Remote DRAM (3 hops) */
+
#define PERF_MEM_S(a, s) \
(((u64)PERF_MEM_##a##_##s) << PERF_MEM_##a##_SHIFT)
--
1.7.1
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