Drop stable from CC. On Thu, Aug 11, 2016 at 04:21:42PM +0100, Matt Fleming wrote: > 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 fill requests > to the L2 and instruction/data cache 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.
I guess that's closer. Even though LLC is not always L2 on AMD (some have L3). Btw, what are the exact events for PERF_COUNT_HW_CACHE_REFERENCES and PERF_COUNT_HW_CACHE_MISSES called on Intel? I could try to find better/more fitting event selectors on AMD... > Signed-off-by: Matt Fleming <[email protected]> > Cc: Peter Zijlstra <[email protected]> > Cc: Ingo Molnar <[email protected]> > Cc: Borislav Petkov <[email protected]> > Cc: <[email protected]> > --- > arch/x86/events/amd/core.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/arch/x86/events/amd/core.c b/arch/x86/events/amd/core.c > index e07a22bb9308..8fd8bf79f32b 100644 > --- a/arch/x86/events/amd/core.c > +++ b/arch/x86/events/amd/core.c > @@ -119,8 +119,8 @@ static const u64 amd_perfmon_event_map[PERF_COUNT_HW_MAX] > = > { > [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] = 0x037d, > + [PERF_COUNT_HW_CACHE_MISSES] = 0x037e, > [PERF_COUNT_HW_BRANCH_INSTRUCTIONS] = 0x00c2, > [PERF_COUNT_HW_BRANCH_MISSES] = 0x00c3, > [PERF_COUNT_HW_STALLED_CYCLES_FRONTEND] = 0x00d0, /* "Decoder empty" > event */ Btw, there's also amd_event_mapping in arch/x86/kvm/pmu_amd.c which has duplicated amd_perfmon_event_map. Would need adjusting too. -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. --
