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From: "Hunter, Adrian" <adrian.hunter@intel.com>
To: Alexey Budankov <alexey.budankov@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>, Andi Kleen <ak@linux.intel.com>,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: RE: [PATCH v6 01/13] tools/libperf: introduce notion of static polled file descriptors
Date: Wed, 3 Jun 2020 12:30:15 +0000	[thread overview]
Message-ID: <363DA0ED52042842948283D2FC38E464B4151F86@IRSMSX106.ger.corp.intel.com> (raw)
In-Reply-To: <eb31a2a4-ab3b-54a7-2d5a-51457f78394e@intel.com>



> -----Original Message-----
> From: Hunter, Adrian <adrian.hunter@intel.com>
> Sent: Wednesday, June 3, 2020 3:24 PM
> To: Alexey Budankov <alexey.budankov@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>; Andi Kleen
> <ak@linux.intel.com>; linux-kernel <linux-kernel@vger.kernel.org>
> Subject: Re: [PATCH v6 01/13] tools/libperf: introduce notion of static polled
> file descriptors
> 
> On 3/06/20 3:01 pm, Alexey Budankov wrote:
> > Hi,
> >
> > On 03.06.2020 14:38, Adrian Hunter wrote:
> >> On 1/06/20 11:05 pm, Alexey Budankov wrote:
> >>>
> >>> Implement adding of file descriptors by fdarray__add_stat() to
> >>> fix-sized (currently 1) stat_entries array located at struct fdarray.
> >>> Append added file descriptors to the array used by poll() syscall
> >>> during fdarray__poll() call. Copy poll() result of the added
> >>> descriptors from the array back to the storage for separate analysis.
> >>
> >> Why not instead call evlist__add_pollfd() before other fds are added,
> >> so the fda->entries[] position is always fixed. Then this patch is not
> needed.
> >
> > It then will block event consumption loop, at least in record mode,
> > due to change sin initial assumptions behind fdarray__filter(). So
> > extension of the API with 'static' fds looks safer w.r.t. possible
> > functional regressions at the same time extending the API with ability
> > to atomically wait for (poll()) not only event fds but also any other fds
> during monitoring.
> 
> So make fdarray__filter() return the number of filterable fds remaining.
> 


Or perhaps simpler, compare the return value to the number of fds that are known not to be filterable

  reply	other threads:[~2020-06-03 12:30 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-01 20:01 [PATCH v6 00/13] perf: support enable and disable commands in stat and record modes Alexey Budankov
2020-06-01 20:05 ` [PATCH v6 01/13] tools/libperf: introduce notion of static polled file descriptors Alexey Budankov
2020-06-03 11:38   ` Adrian Hunter
2020-06-03 12:01     ` Alexey Budankov
2020-06-03 12:23       ` Adrian Hunter
2020-06-03 12:30         ` Hunter, Adrian [this message]
2020-06-03 12:52           ` Alexey Budankov
2020-06-03 15:53             ` Adrian Hunter
2020-06-03 17:00               ` Alexey Budankov
2020-06-01 20:06 ` [PATCH v6 02/13] perf evlist: introduce control " Alexey Budankov
2020-06-01 20:07 ` [PATCH v6 03/13] perf evlist: implement control command handling functions Alexey Budankov
2020-06-01 20:08 ` [PATCH v6 04/13] perf stat: factor out body of event handling loop for system wide Alexey Budankov
2020-06-01 20:08 ` [PATCH v6 05/13] perf stat: move target check to loop control statement Alexey Budankov
2020-06-01 20:09 ` [PATCH v6 06/13] perf stat: factor out body of event handling loop for fork case Alexey Budankov
2020-06-01 20:10 ` [PATCH v6 07/13] perf stat: factor out event handling loop into dispatch_events() Alexey Budankov
2020-06-01 20:15 ` [PATCH v6 08/13] perf stat: extend -D,--delay option with -1 value Alexey Budankov
2020-06-01 20:17 ` [PATCH v6 09/13] perf stat: implement control commands handling Alexey Budankov
2020-06-01 20:17 ` [PATCH v6 10/13] perf stat: introduce --ctl-fd[-ack] options Alexey Budankov
2020-06-01 20:18 ` [PATCH v6 11/13] perf record: extend -D,--delay option with -1 value Alexey Budankov
2020-06-01 20:19 ` [PATCH v6 12/13] perf record: implement control commands handling Alexey Budankov
2020-06-01 20:20 ` [PATCH v6 13/13] perf record: introduce --ctl-fd[-ack] options Alexey Budankov
2020-06-03 12:24   ` Adrian Hunter
2020-06-03 12:52     ` Alexey Budankov

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