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Subject: Re: [PATCH v5 13/13] perf record: introduce --ctl-fd[-ack] options
To:     Alexey Budankov <alexey.budankov@linux.intel.com>,
        Andi Kleen <ak@linux.intel.com>
Cc:     Arnaldo Carvalho de Melo <acme@kernel.org>,
        Jiri Olsa <jolsa@redhat.com>,
        Namhyung Kim <namhyung@kernel.org>,
        Alexander Shishkin <alexander.shishkin@linux.intel.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Ingo Molnar <mingo@redhat.com>,
        linux-kernel <linux-kernel@vger.kernel.org>
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 <d7924d7c-e2e5-c067-b9e0-cfea919e7780@linux.intel.com>
From:   Adrian Hunter <adrian.hunter@intel.com>
Organization: Intel Finland Oy, Registered Address: PL 281, 00181 Helsinki,
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Message-ID: <935187e8-6fc8-5f47-b88d-6e8c92a27286@intel.com>
Date:   Tue, 2 Jun 2020 16:43:58 +0300
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On 2/06/20 12:12 pm, Alexey Budankov wrote:
> 
> On 02.06.2020 11:32, Alexey Budankov wrote:
>>
>> On 02.06.2020 2:37, Andi Kleen wrote:
>>>>> or a pathname, or including also the event default of "disabled".
>>>>
>>>> For my cases conversion of pathnames into open fds belongs to external
>>>> controlling process e.g. like in the examples provided in the patch set.
>>>> Not sure about "event default of 'disabled'"
>>>
>>> It would be nicer for manual use cases if perf supported the path names
>>> directly like in Adrian's example, not needing a complex wrapper script.
>>
>> fds interface is required for VTune integration since VTune wants control
>> over files creation aside of Perf tool process. The script demonstrates
>> just one possible use case.
>>
>> Control files could easily be implemented on top of fds making open operations
>> for paths and then initializing fds. Interface below is vague and with explicit
>> options like below it could be more explicit:
>> --ctl-file /tmp/my-perf.fifo --ctl-file-ack /tmp/my-perf-ack.fifo
> 
> Or even clearer:
> 
> --ctl-fifo /tmp/my-perf --ctl-fifo-ack /tmp/my-perf-ack

If people are OK with having so many options, then that is fine by me.

> 
>>
>> Make either fds and or files provided on the command line. Implement file
>> options handling callbacks that would open paths and setting fds. Close fds
>> if they were opened by Perf tool process.
>>
>> Adrian, please share your mind and use case.
>>
>> ~Alexey
>>
>>>
>>> -Andi
>>>>
>>>>>
>>>>> e.g. add "--control" and support all of:
>>>>>
>>>>> --control
>>>>> --control 11
>>>>> --control 11,15
>>>>> --control 11,15,disabled
>>>>> --control 11,,disabled
>>>>> --control /tmp/my-perf.fifo
>>>>> --control /tmp/my-perf.fifo,/tmp/my-perf-ack.fifo
>>>>> --control /tmp/my-perf.fifo,/tmp/my-perf-ack.fifo,disabled
>>>>> --control /tmp/my-perf.fifo,,disabled
>>>>>
>>>>> Regards
>>>>> Adrian
>>>>>
>>>>
>>>> Regards,
>>>> Alexey
>>>>