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Subject: Re: [PATCH v5 13/13] perf record: introduce --ctl-fd[-ack] options
To:     Adrian Hunter <adrian.hunter@intel.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>
Cc:     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>,
        Andi Kleen <ak@linux.intel.com>,
        linux-kernel <linux-kernel@vger.kernel.org>
References: <e5cac8dd-7aa4-ec7c-671c-07756907acba@linux.intel.com>
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 <923c40c7-7c0b-9fad-314d-69e7acbee201@intel.com>
From:   Alexey Budankov <alexey.budankov@linux.intel.com>
Organization: Intel Corp.
Message-ID: <937c8cc1-b4c2-8531-3fa4-d0ad9df6a65f@linux.intel.com>
Date:   Mon, 1 Jun 2020 20:11:35 +0300
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Hi Adrian,

On 01.06.2020 19:30, Adrian Hunter wrote:
> On 1/06/20 7:05 pm, Alexey Budankov wrote:
>>
>> Introduce --ctl-fd[-ack] options to pass open file descriptors numbers
>> from command line. Extend perf-record.txt file with --ctl-fd[-ack]
>> options description. Document possible usage model introduced by
>> --ctl-fd[-ack] options by providing example bash shell script.
> 
> Hi
> 
> I am interested in using this also for taking snapshots.

Good to hear from you.

> 
> Did you consider using a single option, or allowing either a file descriptor

Single option use case is already possible like --ctl-fd <NUM_1>.
Synchronization messages can be provided via --ctl-fd-ack <NUM_2>.

> 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'"

> 
> 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