linux-kernel - Re: [PATCH v1 5/5] perf test trace BTF: Use --sort-events in BTF general tests

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Message-ID: <CAH0uvohjmuahjP1Xrz3h9FmK7R1zE_jP-czxt2s_5pPx_nMu2w@mail.gmail.com>
Date: Sun, 18 May 2025 11:11:55 -0700
From: Howard Chu <howardchu95@...il.com>
To: Namhyung Kim <namhyung@...nel.org>
Cc: acme@...nel.org, mingo@...hat.com, mark.rutland@....com, 
	alexander.shishkin@...ux.intel.com, jolsa@...nel.org, irogers@...gle.com, 
	adrian.hunter@...el.com, peterz@...radead.org, kan.liang@...ux.intel.com, 
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 5/5] perf test trace BTF: Use --sort-events in BTF
 general tests

Hello Namhyung,

On Sun, May 18, 2025 at 10:51 AM Namhyung Kim <namhyung@...nel.org> wrote:
>
> On Sat, May 17, 2025 at 09:32:30AM -0700, Howard Chu wrote:
> > Without the '--sort-events' flag, perf trace doesn't receive and process
> > events based on their arrival time, thus PERF_RECORD_COMM event that
> > assigns the correct comm to a PID, may be delivered and processed after
> > regular samples, causing trace outputs not having a 'comm', e.g.
> > 'mv', instead, having the default PID placeholder, e.g. ':14514'.
> >
> > Hopefully this answers Namhyung's question in [1].
>
> Thanks, it makes sense.  Maybe it migrated to another CPU after exec.
>
> >
> > You can simply justify the statement with this diff:
> >
> > ---8<---
>
> Please do not use this in the format patch emails.  This makes git treat
> the following contents as commit body so it'll be added to the commit as
> if it's a valid change.  Maybe adding some spaces at the beginning of
> each line help.  But I think it's better if you publish it somewhere else
> and add a link instead.

Sorry. I will delete this scissor in v2.

Thanks,
Howard