linux-kernel - RE: [RFC PATCH v18 8/8] perf test: Add test for Intel TPEBS counting mode

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Message-ID: <CO6PR11MB5635B87159218287A4E8108CEE862@CO6PR11MB5635.namprd11.prod.outlook.com>
Date: Tue, 13 Aug 2024 17:18:22 +0000
From: "Wang, Weilin" <weilin.wang@...el.com>
To: Arnaldo Carvalho de Melo <acme@...nel.org>
CC: Namhyung Kim <namhyung@...nel.org>, Ian Rogers <irogers@...gle.com>, Peter
 Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, Alexander
 Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>,
	"Hunter, Adrian" <adrian.hunter@...el.com>, Kan Liang
	<kan.liang@...ux.intel.com>, "linux-perf-users@...r.kernel.org"
	<linux-perf-users@...r.kernel.org>, "linux-kernel@...r.kernel.org"
	<linux-kernel@...r.kernel.org>, "Taylor, Perry" <perry.taylor@...el.com>,
	"Alt, Samantha" <samantha.alt@...el.com>, "Biggers, Caleb"
	<caleb.biggers@...el.com>
Subject: RE: [RFC PATCH v18 8/8] perf test: Add test for Intel TPEBS counting
 mode



> -----Original Message-----
> From: Arnaldo Carvalho de Melo <acme@...nel.org>
> Sent: Monday, August 12, 2024 6:26 PM
> To: Wang, Weilin <weilin.wang@...el.com>
> Cc: Namhyung Kim <namhyung@...nel.org>; Ian Rogers
> <irogers@...gle.com>; Peter Zijlstra <peterz@...radead.org>; Ingo Molnar
> <mingo@...hat.com>; Alexander Shishkin
> <alexander.shishkin@...ux.intel.com>; Jiri Olsa <jolsa@...nel.org>; Hunter,
> Adrian <adrian.hunter@...el.com>; Kan Liang <kan.liang@...ux.intel.com>;
> linux-perf-users@...r.kernel.org; linux-kernel@...r.kernel.org; Taylor, Perry
> <perry.taylor@...el.com>; Alt, Samantha <samantha.alt@...el.com>; Biggers,
> Caleb <caleb.biggers@...el.com>
> Subject: Re: [RFC PATCH v18 8/8] perf test: Add test for Intel TPEBS counting
> mode
> 
> On Mon, Aug 12, 2024 at 10:24:40PM -0300, Arnaldo Carvalho de Melo
> wrote:
> > On Sat, Jul 20, 2024 at 02:21:01AM -0400, weilin.wang@...el.com wrote:
> > > From: Weilin Wang <weilin.wang@...el.com>
> > >
> > > Intel TPEBS sampling mode is supported through perf record. The counting
> mode
> > > code uses perf record to capture retire_latency value and use it in metric
> > > calculation. This test checks the counting mode code on Intel platforms.
> >
> > root@x1:~# perf test -vvvvv 123
> > 123: test Intel TPEBS counting mode:
> > --- start ---
> > test child forked, pid 2600160
> > Testing without --record-tpebs
> > Testing with --record-tpebs
> > ---- end(-1) ----
> > 123: test Intel TPEBS counting mode                                  : FAILED!
> > root@x1:~# grep -m1 "model name" /proc/cpuinfo
> > model name	: 13th Gen Intel(R) Core(TM) i7-1365U
> > root@x1:~#
> >
> > What am I missing?
> >
> > The current codebase is in tmp.perf-tools-next
> 
> acme@x1:~/git/perf-tools-next$ uname -a
> Linux x1 6.8.11-200.fc39.x86_64 #1 SMP PREEMPT_DYNAMIC Sun May 26
> 20:05:41 UTC 2024 x86_64 GNU/Linux
> 

Hi Arnaldo,
I just checkout the code and tested it. The failure is caused by a seg fault on a
perf_tool struct that is not initialized correctly. I think this is related to the patches 
on struct perf_tool in this branch that applied right before the tpebs patches. 

I was able to fix the seg fault by adding the perf_tool__fill_defaults() back. Since 
Ian updated the code to replace this function, I think I need some advice on how 
to use the new code to initialize perf_tool correctly here. Should I call the 
perf_tool__init()?


Thanks,
Weilin


> > - Arnaldo
> >
> > > Signed-off-by: Weilin Wang <weilin.wang@...el.com>
> > > ---
> > >  .../perf/tests/shell/test_stat_intel_tpebs.sh | 19 +++++++++++++++++++
> > >  1 file changed, 19 insertions(+)
> > >  create mode 100755 tools/perf/tests/shell/test_stat_intel_tpebs.sh
> > >
> > > diff --git a/tools/perf/tests/shell/test_stat_intel_tpebs.sh
> b/tools/perf/tests/shell/test_stat_intel_tpebs.sh
> > > new file mode 100755
> > > index 000000000000..c60b29add980
> > > --- /dev/null
> > > +++ b/tools/perf/tests/shell/test_stat_intel_tpebs.sh
> > > @@ -0,0 +1,19 @@
> > > +#!/bin/bash
> > > +# test Intel TPEBS counting mode
> > > +# SPDX-License-Identifier: GPL-2.0
> > > +
> > > +set -e
> > > +grep -q GenuineIntel /proc/cpuinfo || { echo Skipping non-Intel; exit 2; }
> > > +
> > > +# Use this event for testing because it should exist in all platforms
> > > +event=cache-misses:R
> > > +
> > > +# Without this cmd option, default value or zero is returned
> > > +echo "Testing without --record-tpebs"
> > > +result=$(perf stat -e "$event" true 2>&1)
> > > +[[ "$result" =~ $event ]] || exit 1
> > > +
> > > +# In platforms that do not support TPEBS, it should execute without error.
> > > +echo "Testing with --record-tpebs"
> > > +result=$(perf stat -e "$event" --record-tpebs -a sleep 0.01 2>&1)
> > > +[[ "$result" =~ "perf record" && "$result" =~ $event ]] || exit 1
> > > --
> > > 2.43.0
> > >