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

From: "Liang, Kan" <kan.liang@linux.intel.com>
To: Thomas Richter <tmricht@linux.ibm.com>,
	kajoljain <kjain@linux.ibm.com>,
	acme@kernel.org, irogers@google.com, peterz@infradead.org,
	mingo@redhat.com, namhyung@kernel.org, jolsa@kernel.org,
	adrian.hunter@intel.com, john.g.garry@oracle.com,
	will@kernel.org, james.clark@arm.com, mike.leach@linaro.org,
	leo.yan@linaro.org, yuhaixin.yhx@linux.alibaba.com,
	renyu.zj@linux.alibaba.com, ravi.bangoria@amd.com,
	atrajeev@linux.vnet.ibm.com, linux-kernel@vger.kernel.org,
	linux-perf-users@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH V3 0/7] Clean up perf mem
Date: Tue, 23 Jan 2024 09:36:37 -0500	[thread overview]
Message-ID: <0d85e3f6-d857-4c62-8ad8-c20ac2665e91@linux.intel.com> (raw)
In-Reply-To: <ceffdc69-982b-4909-95df-5b6a8a277f20@linux.ibm.com>

On 2024-01-23 12:56 a.m., Thomas Richter wrote:
> On 1/23/24 06:30, kajoljain wrote:
>>
>>
>> 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
>>
> 
> s390 does not support perf mem at all. Right now it is save to remove it from s390.

Thanks for the confirmation!

Thanks,
Kan

> Thanks
> 
>>>
>>> Thanks,
>>> Kan
>>
> 

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