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| author | Matt Fleming <matt@codeblueprint.co.uk> | 2016-08-24 14:12:08 +0100 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2016-11-20 01:17:30 +0000 |
| commit | 9371773db47affedd29a857e8707f16562cc94b4 (patch) | |
| tree | 87c1b07cb1b7259fd4984c82eec4135983ead697 | |
| parent | 755b0ecbe124df0fa5a58032918d30231b337615 (diff) | |
| download | lwn-9371773db47affedd29a857e8707f16562cc94b4.tar.gz lwn-9371773db47affedd29a857e8707f16562cc94b4.zip | |
perf/x86/amd: Make HW_CACHE_REFERENCES and HW_CACHE_MISSES measure L2
commit 080fe0b790ad438fc1b61621dac37c1964ce7f35 upstream.
While the Intel PMU monitors the LLC when perf enables the
HW_CACHE_REFERENCES and HW_CACHE_MISSES events, these events monitor
L1 instruction cache fetches (0x0080) and instruction cache misses
(0x0081) on the AMD PMU.
This is extremely confusing when monitoring the same workload across
Intel and AMD machines, since parameters like,
$ perf stat -e cache-references,cache-misses
measure completely different things.
Instead, make the AMD PMU measure instruction/data cache and TLB fill
requests to the L2 and instruction/data cache and TLB misses in the L2
when HW_CACHE_REFERENCES and HW_CACHE_MISSES are enabled,
respectively. That way the events measure unified caches on both
platforms.
Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1472044328-21302-1-git-send-email-matt@codeblueprint.co.uk
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[bwh: Backported to 3.16:
- Drop KVM PMU changes
- Adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | arch/x86/kernel/cpu/perf_event_amd.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/kernel/cpu/perf_event_amd.c b/arch/x86/kernel/cpu/perf_event_amd.c index beeb7cc07044..dc4c3b89c3f5 100644 --- a/arch/x86/kernel/cpu/perf_event_amd.c +++ b/arch/x86/kernel/cpu/perf_event_amd.c @@ -119,8 +119,8 @@ static const u64 amd_perfmon_event_map[] = { [PERF_COUNT_HW_CPU_CYCLES] = 0x0076, [PERF_COUNT_HW_INSTRUCTIONS] = 0x00c0, - [PERF_COUNT_HW_CACHE_REFERENCES] = 0x0080, - [PERF_COUNT_HW_CACHE_MISSES] = 0x0081, + [PERF_COUNT_HW_CACHE_REFERENCES] = 0x077d, + [PERF_COUNT_HW_CACHE_MISSES] = 0x077e, [PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = 0x00c2, [PERF_COUNT_HW_BRANCH_MISSES] = 0x00c3, [PERF_COUNT_HW_STALLED_CYCLES_FRONTEND] = 0x00d0, /* "Decoder empty" event */ |