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Subject: Re: [PATCH v4 10/10] 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: <653fe5f3-c986-a841-1ed8-0a7d2fa24c00@linux.intel.com>
 <cd791bc8-2609-a136-a833-1dab6df68ff2@linux.intel.com>
 <b4b2ddb9-296b-c260-32ef-fee17e04a29d@intel.com>
 <17506256-ef3d-e3a2-a655-a9059b652785@linux.intel.com>
 <3efb178e-19b9-2fca-e1c8-9dcfd4a3ac2c@intel.com>
From:   Alexey Budankov <alexey.budankov@linux.intel.com>
Organization: Intel Corp.
Message-ID: <9a318e1c-06a0-5671-b4d3-10e3cd2d1525@linux.intel.com>
Date:   Wed, 3 Jun 2020 18:52:16 +0300
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On 03.06.2020 18:44, Adrian Hunter wrote:
> On 3/06/20 3:52 pm, Alexey Budankov wrote:
>>
>> On 03.06.2020 15:05, Adrian Hunter wrote:
>>> On 25/05/20 5:23 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.
>>>>
>>>> Signed-off-by: Alexey Budankov <alexey.budankov@linux.intel.com>
>>>> ---
>>>>  tools/perf/Documentation/perf-record.txt | 39 ++++++++++++++++++++++++
>>>>  tools/perf/builtin-record.c              | 10 ++++++
>>>>  tools/perf/util/record.h                 |  2 ++
>>>>  3 files changed, 51 insertions(+)
>>>>
>>>> diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
>>>> index c2c4ce7ccee2..5c012cfe68a4 100644
>>>> --- a/tools/perf/Documentation/perf-record.txt
>>>> +++ b/tools/perf/Documentation/perf-record.txt
>>>> @@ -614,6 +614,45 @@ appended unit character - B/K/M/G
>>>>  	The number of threads to run when synthesizing events for existing processes.
>>>>  	By default, the number of threads equals 1.
>>>>  
>>>> +--ctl-fd::
>>>> +--ctl-fd-ack::
>>>> +Listen on ctl-fd descriptor for command to control measurement ('enable': enable events,
>>>> +'disable': disable events. Optionally send control command completion ('ack') to fd-ack
>>>> +descriptor to synchronize with the controlling process. 
>>>
>>> You should also explain the use of --delay=-1 here.
>>
>> Well, possibly like this:
>>
>> "Listen on ctl-fd descriptor for command to control measurement ('enable': enable events,
>>  'disable': disable events). Measurements can be started paused using --delay=-1 option.
> 
> Instead of:
> 
> "Measurements can be started paused using --delay=-1 option."
> 
> perhaps:
> 
> "To start with events disabled, the --delay=-1 option can be used."

Exactly. In v7.