linux-kernel - Re: [PATCH v2 0/8] Run tests in parallel showing number of tests running

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Message-ID: <CAP-5=fXaiZS3sUctP9K=h5cgaL1dFsuWbhhJFfM4=Avg+xduPw@mail.gmail.com>
Date: Thu, 17 Oct 2024 05:49:12 -0700
From: Ian Rogers <irogers@...gle.com>
To: Namhyung Kim <namhyung@...nel.org>
Cc: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>, 
	Arnaldo Carvalho de Melo <acme@...nel.org>, Mark Rutland <mark.rutland@....com>, 
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>, 
	Adrian Hunter <adrian.hunter@...el.com>, Kan Liang <kan.liang@...ux.intel.com>, 
	James Clark <james.clark@...aro.org>, Howard Chu <howardchu95@...il.com>, 
	Athira Jajeev <atrajeev@...ux.vnet.ibm.com>, Michael Petlan <mpetlan@...hat.com>, 
	Veronika Molnarova <vmolnaro@...hat.com>, Dapeng Mi <dapeng1.mi@...ux.intel.com>, 
	Thomas Richter <tmricht@...ux.ibm.com>, Ilya Leoshkevich <iii@...ux.ibm.com>, 
	Colin Ian King <colin.i.king@...il.com>, Weilin Wang <weilin.wang@...el.com>, 
	Andi Kleen <ak@...ux.intel.com>, linux-kernel@...r.kernel.org, 
	linux-perf-users@...r.kernel.org
Subject: Re: [PATCH v2 0/8] Run tests in parallel showing number of tests running

On Wed, Oct 16, 2024 at 5:28 PM Ian Rogers <irogers@...gle.com> wrote:
>
> On Wed, Oct 16, 2024 at 4:49 PM Namhyung Kim <namhyung@...nel.org> wrote:
> >
> > On Fri, Oct 11, 2024 at 03:03:46PM -0700, Ian Rogers wrote:
> > > Avoid waitpid so that stdout/stderr aren't destroyed prior to wanting
> > > to read them for display. When running on a color terminal, display
> > > the number of running tests (1 if sequential). To avoid previous
> > > flicker, only delete and refresh the display line when it changes. An
> > > earlier version of this code is here:
> > > https://lore.kernel.org/lkml/20240701044236.475098-1-irogers@google.com/
> > >
> > > Add a signal handler for perf tests so that unexpected signals are
> > > displayed and test clean up is possible.
> > >
> > > In perf test add an "exclusive" flag that causes a test to be run with
> > > no other test. Set this flag manually for C tests and via a
> > > "(exclusive)" in the test description for shell tests. Add the flag to
> > > shell tests that may fail when run with other tests.
> > >
> > > Change the perf test loop to run in two passes. For parallel
> > > execution, the first pass runs all tests that can be run in parallel
> > > then the 2nd runs remaining tests sequentially. This causes the
> > > "exclusive" tests to be run last and with test numbers moderately out
> > > of alignment.
> > >
> > > Change the default to be to run tests in parallel. Running tests in
> > > parallel brings the execution time down to less than half.
> > >
> > > v2: Fix inaccurate remaining counts when running specific
> > >     tests. Rename "remaining" to "active" to better reflect the
> > >     testing behavior. Move the exclusive flag to test cases and not
> > >     entire suites. Add more "(exclusive)" flags to test as
> > >     suggested-by James Clark. Remove "(exclusive)" flag from test
> > >     descriptions to keep the command line output more concise. Add
> > >     James Clark's tested-by.
> > >
> > > Ian Rogers (8):
> > >   tools subcmd: Add non-waitpid check_if_command_finished()
> > >   perf test: Display number of active running tests
> > >   perf test: Reduce scope of parallel variable
> > >   perf test: Avoid list test blocking on writing to stdout
> > >   perf test: Tag parallel failing shell tests with "(exclusive)"
> > >   perf test: Add a signal handler around running a test
> > >   perf test: Run parallel tests in two passes
> > >   perf test: Make parallel testing the default
> >
> > Nice work!  It looks much better now.
> >
> > But I'm seeing more failures in parallel mode.  Maybe we want to
> > keep the default serial mode for a little more.
>
> As you say, I think we should be conservative and mark all tests that
> need to serial/sequential/exclusive with the exclusive tag. If you
> tell me the failing tests I can add them to 'perf test: Tag parallel
> failing shell tests with "(exclusive)"' as I did for James Clark with
> the ARM tests. I'd prefer we did the tagging rather than not enabling
> parallel testing as otherwise I may never learn which tests fail for
> people when run in parallel.

With repeat testing, most often for me it was fine, I was able to get
a flake on the probe plus vfs_getname tests like:
```
$ sudo /tmp/perf/perf test vfs -v
91: Add vfs_getname probe to get syscall args filenames             : Ok
--- start ---
test child forked, pid 466904
Failed to write event: File exists
 Error: Failed to add events.
---- end(-1) ----
93: Use vfs_getname probe to get syscall args filenames             : FAILED!
--- start ---
test child forked, pid 466906
Error: event "vfs_getname" already exists.
Hint: Remove existing event by 'perf probe -d'
      or force duplicates by 'perf probe -f'
      or set 'force=yes' in BPF source.
 Error: Failed to add events.
---- end(-1) ----
127: Check open filename arg using perf trace + vfs_getname          : FAILED!
```
So I'll make those exclusive in v2 too. If you could let me know of others.

Thanks,
Ian

> > >
> > >  tools/lib/subcmd/run-command.c                |  33 +++
> > >  tools/perf/tests/builtin-test.c               | 274 ++++++++++++------
> > >  .../tests/shell/coresight/asm_pure_loop.sh    |   2 +-
> > >  .../shell/coresight/memcpy_thread_16k_10.sh   |   2 +-
> > >  .../coresight/thread_loop_check_tid_10.sh     |   2 +-
> > >  .../coresight/thread_loop_check_tid_2.sh      |   2 +-
> > >  .../shell/coresight/unroll_loop_thread_10.sh  |   2 +-
> > >  tools/perf/tests/shell/list.sh                |   5 +-
> > >  .../tests/shell/perftool-testsuite_report.sh  |   2 +-
> > >  tools/perf/tests/shell/record.sh              |   2 +-
> > >  tools/perf/tests/shell/record_lbr.sh          |   2 +-
> > >  tools/perf/tests/shell/record_offcpu.sh       |   2 +-
> > >  tools/perf/tests/shell/stat_all_pmu.sh        |   2 +-
> > >  tools/perf/tests/shell/test_arm_coresight.sh  |   2 +-
> > >  .../tests/shell/test_arm_coresight_disasm.sh  |   2 +-
> > >  tools/perf/tests/shell/test_arm_spe.sh        |   2 +-
> > >  tools/perf/tests/shell/test_intel_pt.sh       |   2 +-
> > >  .../perf/tests/shell/test_stat_intel_tpebs.sh |   2 +-
> > >  tools/perf/tests/task-exit.c                  |   9 +-
> > >  tools/perf/tests/tests-scripts.c              |   7 +-
> > >  tools/perf/tests/tests.h                      |   9 +
> > >  tools/perf/util/color.h                       |   1 +
> > >  22 files changed, 258 insertions(+), 110 deletions(-)
> > >
> > > --
> > > 2.47.0.rc1.288.g06298d1525-goog
> > >