perf scripts python: Add a script to run instances of 'perf script' in parallel

Add a Python script to run a perf script command multiple times in
parallel, using perf script options --cpu and --time so that each job
processes a different chunk of the data.

Extend perf script tests to test also the new script.

The script supports the use of normal 'perf script' options like
--dlfilter and --script, so that the benefit of running parallel jobs
naturally extends to them also. In addition, a command can be provided
(refer --pipe-to option) to pipe standard output to a custom command.

Refer to the script's own help text at the end of the patch for more
details.

The script is useful for Intel PT traces, that can be efficiently
decoded by 'perf script' when split by CPU and/or time ranges. Running
jobs in parallel can decrease the overall decoding time.

Committer testing:

  Ian reported that shellcheck found some issues, I installed it as there
  are no warnings about it not being available, but when available it
  fails the build with:

    TEST    /tmp/build/perf-tools-next/tests/shell/script.sh.shellcheck_log
    CC      /tmp/build/perf-tools-next/util/header.o

  In tests/shell/script.sh line 20:
                  rm -rf "${temp_dir}/"*
                         ^-------------^ SC2115 (warning): Use "${var:?}" to ensure this never expands to /* .

  In tests/shell/script.sh line 83:
          output1_dir="${temp_dir}/output1"
          ^---------^ SC2034 (warning): output1_dir appears unused. Verify use (or export if used externally).

  In tests/shell/script.sh line 84:
          output2_dir="${temp_dir}/output2"
          ^---------^ SC2034 (warning): output2_dir appears unused. Verify use (or export if used externally).

  In tests/shell/script.sh line 86:
          python3 "${pp}" -o "${output_dir}" --jobs 4 --verbose -- perf script -i "${perf_data}"
                              ^-----------^ SC2154 (warning): output_dir is referenced but not assigned (did you mean 'output1_dir'?).

  For more information:
    https://www.shellcheck.net/wiki/SC2034 -- output1_dir appears unused. Verif...
    https://www.shellcheck.net/wiki/SC2115 -- Use "${var:?}" to ensure this nev...
    https://www.shellcheck.net/wiki/SC2154

 -- output_dir is referenced but not ...

Did these fixes:

  -               rm -rf "${temp_dir}/"*
  +               rm -rf "${temp_dir:?}/"*

And:

   @@ -83,8 +83,8 @@ test_parallel_perf()
          output1_dir="${temp_dir}/output1"
          output2_dir="${temp_dir}/output2"
          perf record -o "${perf_data}" --sample-cpu uname
  -       python3 "${pp}" -o "${output_dir}" --jobs 4 --verbose -- perf script -i "${perf_data}"
  -       python3 "${pp}" -o "${output_dir}" --jobs 4 --verbose --per-cpu -- perf script -i "${perf_data}"
  +       python3 "${pp}" -o "${output1_dir}" --jobs 4 --verbose -- perf script -i "${perf_data}"
  +       python3 "${pp}" -o "${output2_dir}" --jobs 4 --verbose --per-cpu -- perf script -i "${perf_data}"

After that:

  root@number:~# perf test -vv "perf script tests"
   97: perf script tests:
  --- start ---
  test child forked, pid 4084139
  DB test
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.032 MB /tmp/perf-test-script.T4MJDr0L6J/perf.data (7 samples) ]
  <SNIP>
  DB test [Success]
  parallel-perf test
  Linux
  [ perf record: Woken up 1 times to write data ]
  [ perf record: Captured and wrote 0.034 MB /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data (7 samples) ]
  Starting: perf script --time=,91898.301878499 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Starting: perf script --time=91898.301878500,91898.301905999 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Starting: perf script --time=91898.301906000,91898.301933499 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Starting: perf script --time=91898.301933500, -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --time=91898.301878500,91898.301905999 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --time=91898.301906000,91898.301933499 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  There are 4 jobs: 2 completed, 2 running
  Finished: perf script --time=,91898.301878499 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --time=91898.301933500, -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  There are 4 jobs: 4 completed, 0 running
  All jobs finished successfully
  parallel-perf.py done
  Starting: perf script --cpu=0 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Starting: perf script --cpu=1 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Starting: perf script --cpu=2 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Starting: perf script --cpu=3 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=0 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=1 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=2 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=3 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  There are 28 jobs: 4 completed, 0 running
  Starting: perf script --cpu=4 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Starting: perf script --cpu=5 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Starting: perf script --cpu=6 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Starting: perf script --cpu=7 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=4 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=5 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=6 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=7 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  There are 28 jobs: 8 completed, 0 running
  Starting: perf script --cpu=8 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Starting: perf script --cpu=9 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Starting: perf script --cpu=10 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Starting: perf script --cpu=11 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=8 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=9 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=10 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=11 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  There are 28 jobs: 12 completed, 0 running
  Starting: perf script --cpu=12 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Starting: perf script --cpu=13 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Starting: perf script --cpu=14 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Starting: perf script --cpu=15 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=12 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=13 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=14 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=15 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  There are 28 jobs: 16 completed, 0 running
  Starting: perf script --cpu=16 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Starting: perf script --cpu=17 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Starting: perf script --cpu=18 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Starting: perf script --cpu=19 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=16 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=17 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=18 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=19 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  There are 28 jobs: 20 completed, 0 running
  Starting: perf script --cpu=20 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Starting: perf script --cpu=21 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Starting: perf script --cpu=22 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Starting: perf script --cpu=23 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=20 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=21 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=22 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=23 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  There are 28 jobs: 24 completed, 0 running
  Starting: perf script --cpu=24 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Starting: perf script --cpu=25 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Starting: perf script --cpu=26 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Starting: perf script --cpu=27 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=25 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=26 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  Finished: perf script --cpu=27 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  There are 28 jobs: 27 completed, 1 running
  Finished: perf script --cpu=24 -i /tmp/perf-test-script.T4MJDr0L6J/pp-perf.data
  There are 28 jobs: 28 completed, 0 running
  All jobs finished successfully
  parallel-perf.py done
  parallel-perf test [Success]
  --- Cleaning up ---
  ---- end(0) ----
   97: perf script tests                                               : Ok
  root@number:~#

Reviewed-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240423133248.10206-1-adrian.hunter@intel.com


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>