On Thu, May 15, 2014 at 9:56 PM, Don Zickus <dzic...@redhat.com> wrote:
> On Thu, May 15, 2014 at 05:56:44PM +0200, Stephane Eranian wrote:
>>
>> This patch fixes a bug in precise_store_data_hsw() whereby
>> it would set the data source memory level to the wrong value.
>>
>> As per the the SDM Vol 3b Table 18-41 (Layout of Data Linear
>> Address Information in PEBS Record), when status bit 0 is set
>> this is a L1 hit, otherwise this is a L1 miss.
>>
>> This patch encodes the memory level according to the specification.
>>
>> In V2, we added the filtering on the store events.
>> Only the following events produce L1 information:
>> * MEM_UOPS_RETIRED.STLB_MISS_STORES
>> * MEM_UOPS_RETIRED.LOCK_STORES
>> * MEM_UOPS_RETIRED.SPLIT_STORES
>> * MEM_UOPS_RETIRED.ALL_STORES
>
> This worked great on our Haswell-EX box. I was a little surprised to find
> out it did until I realized on Ivy Bridge 'mem-store' was a 0x02cd but on
> Haswell it is now a 0x82d0. Go generic event types! :-)
>
> Looking at the SDM documentation it does say something about
> 'UOPS_RETIRED.ALL' supporting stores too but can't find that event. Is
> that a typo, much like the 0x02 umask for stores on the D0 event is
> missing from the documentation? Just wanted to make sure we are not
> missing one more case.
>
But uops_retired.all does not generate the L1 info. That is why it is not
there in my patch.
> Thanks for the quick patch Stephane!
>
> Tested-and-Reviewed-by: Don Zickus <dzic...@redhat.com>
>
>>
>> Signed-off-by: Stephane Eranian <eran...@google.com>
>>
>> diff --git a/arch/x86/kernel/cpu/perf_event_intel_ds.c
>> b/arch/x86/kernel/cpu/perf_event_intel_ds.c
>> index ae96cfa..980970c 100644
>> --- a/arch/x86/kernel/cpu/perf_event_intel_ds.c
>> +++ b/arch/x86/kernel/cpu/perf_event_intel_ds.c
>> @@ -108,15 +108,31 @@ static u64 precise_store_data(u64 status)
>> return val;
>> }
>>
>> -static u64 precise_store_data_hsw(u64 status)
>> +static u64 precise_store_data_hsw(struct perf_event *event, u64 status)
>> {
>> union perf_mem_data_src dse;
>> + u64 cfg = event->hw.config & INTEL_ARCH_EVENT_MASK;
>>
>> dse.val = 0;
>> dse.mem_op = PERF_MEM_OP_STORE;
>> dse.mem_lvl = PERF_MEM_LVL_NA;
>> +
>> + /*
>> + * L1 info only valid for following events:
>> + *
>> + * MEM_UOPS_RETIRED.STLB_MISS_STORES
>> + * MEM_UOPS_RETIRED.LOCK_STORES
>> + * MEM_UOPS_RETIRED.SPLIT_STORES
>> + * MEM_UOPS_RETIRED.ALL_STORES
>> + */
>> + if (cfg != 0x12d0 && cfg != 0x22d0 && cfg != 0x42d0 && cfg != 0x82d0)
>> + return dse.mem_lvl;
>> +
>> if (status & 1)
>> - dse.mem_lvl = PERF_MEM_LVL_L1;
>> + dse.mem_lvl = PERF_MEM_LVL_L1 | PERF_MEM_LVL_HIT;
>> + else
>> + dse.mem_lvl = PERF_MEM_LVL_L1 | PERF_MEM_LVL_MISS;
>> +
>> /* Nothing else supported. Sorry. */
>> return dse.val;
>> }
>> @@ -887,7 +903,7 @@ static void __intel_pmu_pebs_event(struct perf_event
>> *event,
>> data.data_src.val =
>> load_latency_data(pebs->dse);
>> else if (event->hw.flags & PERF_X86_EVENT_PEBS_ST_HSW)
>> data.data_src.val =
>> - precise_store_data_hsw(pebs->dse);
>> + precise_store_data_hsw(event,
>> pebs->dse);
>> else
>> data.data_src.val =
>> precise_store_data(pebs->dse);
>> }
--
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