linux-kernel - Re: [PATCH v3 0/3] perf: add new option '--workload-attr' to set workload sched

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Date:   Mon, 24 Jul 2023 17:34:18 +0800
From:   Changbin Du <changbin.du@...wei.com>
To:     Adrian Hunter <adrian.hunter@...el.com>
CC:     Changbin Du <changbin.du@...wei.com>,
        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>,
        Namhyung Kim <namhyung@...nel.org>,
        Ian Rogers <irogers@...gle.com>,
        <linux-perf-users@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        Hui Wang <hw.huiwang@...wei.com>
Subject: Re: [PATCH v3 0/3] perf: add new option '--workload-attr' to set
 workload sched_policy/priority/mask

On Mon, Jul 24, 2023 at 08:44:12AM +0300, Adrian Hunter wrote:
> 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?
> 
> > 
There is no problem with a script, just a shortcut for convenience. When I want
to share perf investigation with somebody, I just need to share a single commandline.
Anyway nothing bad, right? :)


-- 
Cheers,
Changbin Du