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

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Message-ID: <a0540796-1933-4057-8282-aa219ddda4fe@linux.intel.com>
Date: Tue, 16 Jan 2024 11:37:02 -0500
From: "Liang, Kan" <kan.liang@...ux.intel.com>
To: kajoljain <kjain@...ux.ibm.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 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.

Thanks,
Kan