linux-kernel - Re: [RFC 4/4] perf sched schedstat: Add support for report subcommand

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Message-ID: <284a27be-bd63-d86c-885f-756bd2d37adc@amd.com>
Date: Mon, 13 May 2024 08:43:32 +0530
From: Ravi Bangoria <ravi.bangoria@....com>
To: Chen Yu <yu.c.chen@...el.com>
Cc: peterz@...radead.org, mingo@...hat.com, acme@...nel.org,
 namhyung@...nel.org, irogers@...gle.com, swapnil.sapkal@....com,
 mark.rutland@....com, alexander.shishkin@...ux.intel.com, jolsa@...nel.org,
 rostedt@...dmis.org, vincent.guittot@...aro.org, bristot@...hat.com,
 adrian.hunter@...el.com, james.clark@....com, kan.liang@...ux.intel.com,
 gautham.shenoy@....com, kprateek.nayak@....com, juri.lelli@...hat.com,
 yangjihong@...edance.com, linux-kernel@...r.kernel.org,
 linux-perf-users@...r.kernel.org, santosh.shukla@....com,
 ananth.narayan@....com, sandipan.das@....com,
 Ravi Bangoria <ravi.bangoria@....com>
Subject: Re: [RFC 4/4] perf sched schedstat: Add support for report subcommand

On 11-May-24 1:15 PM, Chen Yu wrote:
> On 2024-05-08 at 11:34:27 +0530, Ravi Bangoria wrote:
>> From: Swapnil Sapkal <swapnil.sapkal@....com>
>>
>> `perf sched schedstat record` captures two sets of samples. For workload
>> profile, first set right before workload starts and second set after
>> workload finishes. For the systemwide profile, first set at the beginning
>> of profile and second set on receiving SIGINT signal.
>>
>> Add `perf sched schedstat report` subcommand that will read both the set
>> of samples, get the diff and render a final report. Final report prints
>> scheduler stat at cpu granularity as well as sched domain granularity.
>>
>> Usage example:
>>
>>   # perf sched schedstat record
>>   # perf sched schedstat report
>>
>> Co-developed-by: Ravi Bangoria <ravi.bangoria@....com>
>> Signed-off-by: Swapnil Sapkal <swapnil.sapkal@....com>
>> Signed-off-by: Ravi Bangoria <ravi.bangoria@....com>
>>
> 
> I've tested it on a 240 CPUs Xeon system and it looks very useful. Thanks!

Glad you found it useful!

> 1. Just to confirm, if we want to add new fields for debugging purpose,
>    schedstat-domain-v1x.h and schedstat-cpu-v1x.h are the only files to
>    be touched, right?

Correct.

> 2. Although we can filter the output, is it applicable to only track some
>    CPUs? Like perf sched schedstat -C 4 record

Yes, adding filtering capabilities should be possible at both record and report
time.

Thanks,
Ravi