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

[Adrian Hunter <adrian.hunter@intel.com>]

On 24/07/23 07:02, Changbin Du wrote:
> 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.

There is also command schedtool, but what exactly is the problem
with a script?

> 
>>
>>>
>>> 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(-)
>>>
>>
>