linux-kernel - Re: [PATCH V3 0/7] Clean up perf mem

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Date: Tue, 23 Jan 2024 11:00:19 +0530
From: kajoljain <kjain@...ux.ibm.com>
To: "Liang, Kan" <kan.liang@...ux.intel.com>, acme@...nel.org,
        irogers@...gle.com, peterz@...radead.org, mingo@...hat.com,
        namhyung@...nel.org, jolsa@...nel.org, adrian.hunter@...el.com,
        john.g.garry@...cle.com, will@...nel.org, james.clark@....com,
        mike.leach@...aro.org, leo.yan@...aro.org,
        yuhaixin.yhx@...ux.alibaba.com, renyu.zj@...ux.alibaba.com,
        tmricht@...ux.ibm.com, ravi.bangoria@....com,
        atrajeev@...ux.vnet.ibm.com, linux-kernel@...r.kernel.org,
        linux-perf-users@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH V3 0/7] Clean up perf mem



On 1/16/24 22:07, Liang, Kan wrote:
> 
> 
> On 2024-01-16 9:05 a.m., kajoljain wrote:
>>> For powerpc, the patch 3 introduced a perf_mem_events_power, which
>>> doesn't have ldlat. But it only be assigned to the pmu->is_core. I'm not
>>> sure if it's the problem.
>> Hi Kan,
>>  Correct there were some small issues with patch 3, I added fix for that.
>>
> 
> Thanks Kajol Jain! I will fold your fix into V4.
> 
>>> Also, S390 still uses the default perf_mem_events, which includes ldlat.
>>> I'm not sure if S390 supports the ldlat.
>> I checked it, I didn't find ldlat parameter defined in arch/s390
>> directory. I think its better to make default ldlat value as false
>> in tools/perf/util/mem-events.c file.
> 
> The s390 may not be the only user for the default perf_mem_events[] in
> the tools/perf/util/mem-events.c. We probably cannot change the default
> value.
> We may share the perf_mem_events_power[] between powerpc and s390. (We
> did the similar share for arm and arm64.)
> 
> How about the below patch (not tested.)
> 
> diff --git a/tools/perf/arch/s390/util/pmu.c
> b/tools/perf/arch/s390/util/pmu.c
> index 225d7dc2379c..411034c984bb 100644
> --- a/tools/perf/arch/s390/util/pmu.c
> +++ b/tools/perf/arch/s390/util/pmu.c
> @@ -8,6 +8,7 @@
>  #include <string.h>
> 
>  #include "../../../util/pmu.h"
> +#include "../../powerpc/util/mem-events.h"
> 
>  #define        S390_PMUPAI_CRYPTO      "pai_crypto"
>  #define        S390_PMUPAI_EXT         "pai_ext"
> @@ -21,5 +22,5 @@ void perf_pmu__arch_init(struct perf_pmu *pmu)
>                 pmu->selectable = true;
> 
>         if (pmu->is_core)
> -               pmu->mem_events = perf_mem_events;
> +               pmu->mem_events = perf_mem_events_power;
>  }
> 
> 
> 
> However, the original s390 code doesn't include any s390 specific code
> for perf_mem. So I thought it uses the default perf_mem_events[].
> Is there something I missed?
> 
> Or does the s390 even support mem events? If not, I may remove the
> mem_events from s390.

Hi Kan,
   I don't have s390 system to do testing. But from my end I am fine
with the changes.

Thanks,
Kajol Jain

> 
> Thanks,
> Kan