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Date:   Mon, 8 Jun 2020 10:45:51 +0200
From:   Jiri Olsa <jolsa@redhat.com>
To:     Alexey Budankov <alexey.budankov@linux.intel.com>
Cc:     Adrian Hunter <adrian.hunter@intel.com>,
        Andi Kleen <ak@linux.intel.com>,
        Arnaldo Carvalho de Melo <acme@kernel.org>,
        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>
Subject: Re: [PATCH v5 13/13] perf record: introduce --ctl-fd[-ack] options
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On Fri, Jun 05, 2020 at 06:23:17PM +0300, Alexey Budankov wrote:

SNIP

> >>>>>> 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.
> >>>>
> >>>> the single option Adrian suggested seems better to me:
> >>>>
> >>>>  --control
> >>>>  --control 11
> >>>>  --control 11,15
> >>>
> >>> What if a user specifies fifos named like this above, not fds?
> >>>
> >>>>  --control 11,15,disabled
> >>>>  --control 11,,disabled
> >>>>  --control /tmp/my-perf.fifo
> >>>>  --control /tmp/my-perf.fifo,/tmp/my-perf-ack.fifo
> >>>
> >>> What if a user wants not fifos but other type of comm channels?
> >>>
> >>>>  --control /tmp/my-perf.fifo,/tmp/my-perf-ack.fifo,disabled
> >>>>  --control /tmp/my-perf.fifo,,disabled
> >>>>
> >>>> we already support this kind of options arguments, like for --call-graph
> >>>>
> >>>> jirka
> >>>>
> >>>
> >>> IMHO,
> >>> this interface, of course, looks more compact (in amount of options) however
> >>> the other side it is less user friendly. One simple option for one simple
> >>> purpose is more convenient as for users as for developers. Also complex
> >>> option syntax tends to have limitations and there are probably more
> >>> non-obvious ones.
> >>>
> >>> Please speak up. I might have missed something meaningful.
> >>
> >> how about specify the type like:
> >>
> >> --control fd:1,2,...
> > 
> > What do these ... mean?
> 
> After all,
> if you want it this way and it now also fits my needs I could convert
> --ctl-fd[-ack] to --control fd:<ctl-fd>,<ack-fd> with use cases like
> --control fd:<ctl-fd> and --control fd:<ctl-fd>,<ack-fd>. Accepted?

looks good

jirka