linux-kernel - Re: [PATCH v2 0/6] perf arm64 metricgroup support

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Date:   Tue, 30 Mar 2021 12:11:37 +0530
From:   kajoljain <kjain@...ux.ibm.com>
To:     "Paul A. Clarke" <pc@...ibm.com>,
        John Garry <john.garry@...wei.com>
Cc:     will@...nel.org, mathieu.poirier@...aro.org, leo.yan@...aro.org,
        peterz@...radead.org, mingo@...hat.com, acme@...nel.org,
        mark.rutland@....com, alexander.shishkin@...ux.intel.com,
        jolsa@...hat.com, namhyung@...nel.org, irogers@...gle.com,
        linuxarm@...wei.com, kan.liang@...ux.intel.com,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        zhangshaokun@...ilicon.com
Subject: Re: [PATCH v2 0/6] perf arm64 metricgroup support



On 3/30/21 2:37 AM, Paul A. Clarke wrote:
> On Fri, Mar 26, 2021 at 10:57:40AM +0000, John Garry wrote:
>> On 25/03/2021 20:39, Paul A. Clarke wrote:
>>> On Thu, Mar 25, 2021 at 06:33:12PM +0800, John Garry wrote:
>>>> Metric reuse support is added for pmu-events parse metric testcase.
>>>> This had been broken on power9 recentlty:
>>>> https://lore.kernel.org/lkml/20210324015418.GC8931@li-24c3614c-2adc-11b2-a85c-85f334518bdb.ibm.com/
>>>
>>> Much better.  Before:
>>> --
>>> $ perf test -v 10 2>&1 | grep -i error | wc -l
>>> 112
>>> --
>>> After:
>>> --
>>> $ perf test -v 10 2>&1 | grep -i error | wc -l
>>> 17
>>> --
>>>
>>> And these seem like different types of issues:
>>> --
>>> $ perf test -v 10 2>&1 | grep -i error
>>> Error string 'Cannot find PMU `nest_mcs01_imc'. Missing kernel support?' help '(null)'
>>> Error string 'Cannot find PMU `nest_mcs01_imc'. Missing kernel support?' help '(null)'
>>> Error string 'Cannot find PMU `nest_mcs23_imc'. Missing kernel support?' help '(null)'
>>> Error string 'Cannot find PMU `nest_mcs23_imc'. Missing kernel support?' help '(null)'
>>> Error string 'Cannot find PMU `nest_mcs01_imc'. Missing kernel support?' help '(null)'
>>> Error string 'Cannot find PMU `nest_mcs01_imc'. Missing kernel support?' help '(null)'
>>> Error string 'Cannot find PMU `nest_mcs23_imc'. Missing kernel support?' help '(null)'
>>> Error string 'Cannot find PMU `nest_mcs23_imc'. Missing kernel support?' help '(null)'
>>> Error string 'Cannot find PMU `nest_powerbus0_imc'. Missing kernel support?' help '(null)'
>>> Error string 'Cannot find PMU `nest_mcs23_imc'. Missing kernel support?' help '(null)'
>>> Error string 'Cannot find PMU `nest_mcs01_imc'. Missing kernel support?' help '(null)'
>>> Error string 'Cannot find PMU `nest_mcs01_imc'. Missing kernel support?' help '(null)'
>>> Error string 'Cannot find PMU `nest_mcs01_imc'. Missing kernel support?' help '(null)'
>>> Error string 'Cannot find PMU `nest_mcs01_imc'. Missing kernel support?' help '(null)'
>>> Error string 'Cannot find PMU `nest_mcs23_imc'. Missing kernel support?' help '(null)'
>>> Error string 'Cannot find PMU `nest_mcs23_imc'. Missing kernel support?' help '(null)'
>>> Error string 'Cannot find PMU `nest_mcs23_imc'. Missing kernel support?' help '(null)'
>>> --
>>>
>>
>> This looks suspicious.
>>
>> Firstly, does /sys/bus/event_source/devices/nest_mcs01_imc (or others,
>> above) exist on your system? I guess not.
>>
>> Secondly, checking Documentation/powerpc/imc.rst, we have examples of:
>> nest_mcs01/PM_MCS01_64B_R...
>>
>> So is the PMU name correct in the metric file for nest_mcs01_imc? Looking at
>> the kernel driver file, arch/powerpc/perf/imc-pmu.c, it seems to be correct.
>> Not sure.
> 
> I ran with a newer kernel, and the above errors disappeared, replaced with
> about 10 of:
> --
> Error string 'Cannot find PMU `hv_24x7'. Missing kernel support?' help '(null)'
> --
> 
> ...but I was running without a hypervisor, so I tried the same kernel on a
> PowerVM-virtualized system and the "hv_24x7" messages went away, but the
> "nest" messages returned.  This may all be expected behavior... I confess
> I haven't followed these new perf capabilities closely.
> 

Hi Paul/John,
   This is something expected. For nest-imc we need bare-metal system and for
hv-24x7 we need VM environment. Since you are checking this test in VM machine,
there nest events are not supported and hence we are getting this error.

Thanks,
Kajol Jain

> It's extremely likely that none of these errors has anything to do with your
> changes. :-
> 
> PC
>