Re: [PATCH] arc: perf: Enable generic "cache-references" and "cache-misses" events

From: Vineet Gupta
Date: Wed Sep 14 2016 - 13:54:03 EST


On 08/26/2016 10:30 AM, Vineet Gupta wrote:
> On 08/25/2016 04:49 AM, Alexey Brodkin wrote:
>> ...
>> [PERF_COUNT_ARC_EDTLB] = "edtlb", /* D-TLB Miss */
>> [PERF_COUNT_ARC_EITLB] = "eitlb", /* I-TLB Miss */
>> +
>> + [PERF_COUNT_HW_CACHE_REFERENCES] = "imemrdc", /* Instr: mem read cached */
>> + [PERF_COUNT_HW_CACHE_MISSES] = "dclm", /* D-cache Load Miss */
>
> I think this is duplicating a mistake we already have. I vaguely remember when
> doing some hackbench profiling last year with range based profiling confined to
> memset routine and saw that L1-dcache-misses was counting zero. This is because it
> only counts LD misses while memset only does ST.

So given that this is the best we got, I'm going to merge this anyways.

-Vineet

>
> Performance counter stats for '/sbin/hackbench':
>
> 0 L1-dcache-misses
> 0 L1-dcache-load-misses
> 1846082 L1-dcache-store-misses
>
>
> @PeterZ do you concur that is wrong and we ought to setup 2 counters to do this
> correctly ?
>
> -Vineet
>