Re: [PATCH v3 0/3] perf: add new option '--workload-attr' to set workload sched_policy/priority/mask

[Changbin Du <changbin.du@huawei.com>]

On Thu, Jul 20, 2023 at 01:00:58PM +0300, Adrian Hunter wrote:
> On 18/07/23 06:33, Changbin Du wrote:
> > This adds a new option '--workload-attr' to set the sched_policy/priority/mask
> > of the workload to reduce system noise.
> > 
> > $ sudo perf stat --workload-attr fifo,40,0-3:7 -- ls
> 
> Not really sold on the need for this, but maybe it could be
> simpler.
> What about just adding a hook for a command (e.g. script) to
> run before exec'ing the workload e.g.
> 
> --configure-workload=blah.sh
> 
> results in perf doing system("blah.sh 12345") where 12345
> is the workload PID.
> 
> Then maybe you could do:
> 
> --configure-workload="taskset -p 0x3"
>
Acctually, we already have such option for perf-stat.

	--post <command>  command to run after to the measured command
        --pre <command>   command to run prior to the measured command

By involving a shell script we can do more complex setup. But sometimes I just
need to set sched attributes. For example, to investigate the impact of
various compiler optimizations. In this case, I don't want a script. This is the
original purpose I try to add this new option.

> 
> > 
> > Please see patch 1/2 for more details.
> > 
> > v3:
> >   - replace taskset with --workload-attr option in documents and tests.
> > v2:
> >   - Use cpu list spec instead of cpu mask number.
> >   - Update documents.
> > 
> > Changbin Du (3):
> >   perf cpumap: Add __perf_cpu_map__new and perf_cpu_map__2_cpuset
> >   perf: add new option '--workload-attr' to set workload
> >     sched_policy/priority/mask
> >   perf: replace taskset with --workload-attr option
> > 
> >  tools/lib/perf/cpumap.c                       |  45 ++++++-
> >  tools/lib/perf/include/perf/cpumap.h          |   4 +
> >  tools/lib/perf/libperf.map                    |   2 +
> >  tools/perf/Documentation/intel-hybrid.txt     |   2 +-
> >  tools/perf/Documentation/perf-record.txt      |   7 ++
> >  tools/perf/Documentation/perf-stat.txt        |   8 +-
> >  tools/perf/builtin-record.c                   |  26 ++++
> >  tools/perf/builtin-stat.c                     |  18 +++
> >  tools/perf/tests/cpumap.c                     |  23 ++++
> >  .../tests/shell/stat_bpf_counters_cgrp.sh     |   2 +-
> >  tools/perf/tests/shell/test_arm_coresight.sh  |   2 +-
> >  tools/perf/tests/shell/test_data_symbol.sh    |   2 +-
> >  tools/perf/tests/shell/test_intel_pt.sh       |   2 +-
> >  tools/perf/util/evlist.c                      | 117 ++++++++++++++++++
> >  tools/perf/util/evlist.h                      |   3 +
> >  tools/perf/util/target.h                      |   9 ++
> >  16 files changed, 263 insertions(+), 9 deletions(-)
> > 
> 

-- 
Cheers,
Changbin Du