linux-kernel - Re: [PATCH 2/3] perf list: Collapse similar events across PMUs

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Message-ID: <20250305094958.GE13418@e132581.arm.com>
Date: Wed, 5 Mar 2025 09:49:58 +0000
From: Leo Yan <leo.yan@....com>
To: James Clark <james.clark@...aro.org>
Cc: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
	Arnaldo Carvalho de Melo <acme@...nel.org>,
	Namhyung Kim <namhyung@...nel.org>,
	Mark Rutland <mark.rutland@....com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Jiri Olsa <jolsa@...nel.org>, Ian Rogers <irogers@...gle.com>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Robin Murphy <robin.murphy@....com>,
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 2/3] perf list: Collapse similar events across PMUs

On Wed, Mar 05, 2025 at 09:35:45AM +0000, Leo Yan wrote:
> On Tue, Mar 04, 2025 at 01:49:14PM +0000, James Clark wrote:
> > Instead of showing multiple line items with the same event name and
> > description, show a single line and concatenate all PMUs that this
> > event can belong to.
> > 
> > Don't do it for json output. Machine readable output doesn't need to be
> > minimized, and changing the "Unit" field to a list type would break
> > backwards compatibility.
> > 
> > Before:
> >  $ perf list -v
> >  ...
> >  br_indirect_spec
> >        [Branch speculatively executed,indirect branch. Unit: armv8_cortex_a53]
> >  br_indirect_spec
> >        [Branch speculatively executed,indirect branch. Unit: armv8_cortex_a57]
> > 
> > After:
> > 
> >  $ perf list -v
> >  ...
> >  br_indirect_spec
> >        [Branch speculatively executed,indirect branch. Unit: armv8_cortex_a53,armv8_cortex_a57]
> 
> From my testing, based on the latest tmp.perf-tools-next branch, I
> need to remove the option '-v'.  Otherwise, the '-v' option will
> enable long event descriptions, in this case, it does _not_ print Unit
> strings at all (see default_print_event() in builtin-list.c).

Ah, actually I worked on the Linux master branch.  After switched to
tmp.perf-tools-next branch, it works pretty well.

  perf list -v 2>&1 | grep br_mis_pred_retired -A 2
  ...
    br_mis_pred_retired
           [Instruction architecturally executed,mispredicted branch.
           Unit:
                   armv9_cortex_a510,armv9_cortex_a710]

Please ignore my previous comment.  The series looks good to me.

Thanks,
Leo

>   default_print_event()
>   {
>     ...
>     if (long_desc && print_state->long_desc) {
>             fprintf(fp, "%*s", 8, "[");
>             wordwrap(fp, long_desc, 8, pager_get_columns(), 0);
>             fprintf(fp, "]\n");
>     } else if (desc && print_state->desc) {
>     ...
>   }
> 
> The command `perf list` would be sufficent.

> 
> Thanks,
> Leo
>