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Message-ID: <5a24632a-4293-3009-e4c6-e81d6ceb8f07@intel.com>
Date:   Mon, 24 Jul 2023 20:51:15 +0300
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Subject: Re: [PATCH v3 0/3] perf: add new option '--workload-attr' to set
 workload sched_policy/priority/mask
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To:     Changbin Du <changbin.du@huawei.com>
Cc:     Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Jiri Olsa <jolsa@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Ian Rogers <irogers@google.com>,
        linux-perf-users@vger.kernel.org, linux-kernel@vger.kernel.org,
        Hui Wang <hw.huiwang@huawei.com>
References: <20230718033355.2960912-1-changbin.du@huawei.com>
 <5889e93b-5ee3-8d59-c2fb-bce7070a1ab2@intel.com>
 <20230724040229.eipq7i43v4xcrq3p@M910t>
 <05b67e8c-6ba0-5774-93fd-d390ac4e3b19@intel.com>
 <20230724093418.ntluetxruz3ufqnl@M910t>
From:   Adrian Hunter <adrian.hunter@intel.com>
Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki,
 Business Identity Code: 0357606 - 4, Domiciled in Helsinki
In-Reply-To: <20230724093418.ntluetxruz3ufqnl@M910t>
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On 24/07/23 12:34, Changbin Du wrote:
> 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? :)

Also depends on what you call a single commandline, since you could
always create the script and run perf in one long line :-)

I would still go for the simpler option: easier to maintain and
potentially more flexible.