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From: Stephane Eranian <eranian@google.com>
To: Jiri Olsa <jolsa@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>,
	Alexey Budankov <alexey.budankov@linux.intel.com>,
	Jiri Olsa <jolsa@kernel.org>, lkml <linux-kernel@vger.kernel.org>,
	Ingo Molnar <mingo@kernel.org>,
	Namhyung Kim <namhyung@kernel.org>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Andi Kleen <ak@linux.intel.com>
Subject: Re: [RFC/PATCH 00/14] perf record: Add support to store data in directory
Date: Mon, 4 Feb 2019 14:44:37 -0800	[thread overview]
Message-ID: <CABPqkBQTpt0dhinJZc+mJ-JNvkU2M9DVx1G65ngWxZxk-eGBVA@mail.gmail.com> (raw)
In-Reply-To: <20190204202818.GC4794@krava>

Jiri,

While you're looking at the output format, I think it would be good
time to simplify the code handling perf.data file.
Today, perf record can emit in two formats: file mode or pipe mode.
This adds complexity in the code and
is error prone as the file mode path is tested more than the pipe mode
path. We have run into multiple issues with
the pipe mode in recent years. There is no real reason why we need to
maintain two formats. If I recall, the pipe format
was introduced because on pipes you cannot lseek to update the headers
and therefore some of the information present as tables
updated on the fly needed to be generated as pseudo records by the
tool. I believe that the pipe format covers all the needs and could
supersede the file mode format. That would simplify code in perf
record and eliminate the risk of errors when new headers
are introduced.

Related to your effort to make perf record multi-threaded, I was
wondering how this would impact pipe mode.
Could you explain?

Thanks.


On Mon, Feb 4, 2019 at 12:28 PM Jiri Olsa <jolsa@redhat.com> wrote:
>
> On Mon, Feb 04, 2019 at 12:05:38PM -0800, Stephane Eranian wrote:
>
> SNIP
>
> > > > > > >
> > > > > > > [jolsa@krava perf]$ ll result_1/
> > > > > > > total 348
> > > > > > > -rw-------. 1 jolsa jolsa 27624 Feb  4 11:35 data.0
> > > > > > > -rw-------. 1 jolsa jolsa 56672 Feb  4 11:35 data.1
> > > > > > > -rw-------. 1 jolsa jolsa 30824 Feb  4 11:35 data.2
> > > > > > > -rw-------. 1 jolsa jolsa 49136 Feb  4 11:35 data.3
> > > > > > > -rw-------. 1 jolsa jolsa 22712 Feb  4 11:35 data.4
> > > > > > > -rw-------. 1 jolsa jolsa 53392 Feb  4 11:35 data.5
> > > > > > > -rw-------. 1 jolsa jolsa 43352 Feb  4 11:35 data.6
> > > > > > > -rw-------. 1 jolsa jolsa 46688 Feb  4 11:35 data.7
> > > > > > > -rw-------. 1 jolsa jolsa  9068 Feb  4 11:35 header
> > > > > >
> > > > > > Awesome. What do you think about having it like this:
> > > > > >
> > > > > >   $ perf record --output result_1.data ... - writes data to a file
> > > > > >
> > > > > >   $ perf record --dir result_1 ... - or even
> > > > > >   $ perf record --output_dir result_1 ... - writes data into a directory
> > > > > >
> > > > > > IMHO, this interface is simpler for a user.
> > > > >
> > > > > yep, seems more convenient.. I'll add it
> > > > >
> > > > But what happens if you do: perf record -o foo --output_dir foo.d?
> > >
> > > Should fail, i.e. either you use single-file or directory output, I
> > > think.
> > >
> > Agreed
>
> ok, will do that
>
> thanks,
> jirka

  reply	other threads:[~2019-02-04 22:44 UTC|newest]

Thread overview: 49+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-02-03 15:30 [RFC/PATCH 00/14] perf record: Add support to store data in directory Jiri Olsa
2019-02-03 15:30 ` [PATCH 01/14] perf tools: Make rm_rf to remove single file Jiri Olsa
2019-02-05 11:33   ` Alexey Budankov
2019-02-05 13:38     ` Jiri Olsa
2019-02-03 15:30 ` [PATCH 02/14] perf session: Add process callback to reader object Jiri Olsa
2019-02-03 15:30 ` [PATCH 03/14] perf data: Move size to struct perf_data_file Jiri Olsa
2019-02-03 15:30 ` [PATCH 04/14] perf data: Add global path holder Jiri Olsa
2019-02-03 15:30 ` [PATCH 05/14] perf data: Make check_backup work over directories Jiri Olsa
2019-02-03 15:30 ` [PATCH 06/14] perf data: Add perf_data__(create_dir|free_dir) functions Jiri Olsa
2019-02-05 11:52   ` Alexey Budankov
2019-02-05 13:42     ` Jiri Olsa
2019-02-05 13:46   ` Arnaldo Carvalho de Melo
2019-02-05 13:53     ` Jiri Olsa
2019-02-03 15:30 ` [PATCH 07/14] perf data: Add perf_data__open_dir_data function Jiri Olsa
2019-02-03 15:30 ` [PATCH 08/14] perf data: Add directory support Jiri Olsa
2019-02-03 15:30 ` [PATCH 09/14] perf data: Don't store auxtrace index for directory data file Jiri Olsa
2019-02-03 15:30 ` [PATCH 10/14] perf data: Add perf_data__update_dir function Jiri Olsa
2019-02-03 15:30 ` [PATCH 11/14] perf data: Make perf_data__size to work over directory Jiri Olsa
2019-02-03 15:30 ` [PATCH 12/14] perf session: Add __perf_session__process_dir_events function Jiri Olsa
2019-02-03 15:30 ` [PATCH 13/14] perf session: Add path to reader object Jiri Olsa
2019-02-03 15:30 ` [PATCH 14/14] perf record: Add --dir option to store data in directory Jiri Olsa
2019-02-05 12:36   ` Alexey Budankov
2019-02-05 13:51     ` Jiri Olsa
2019-02-04 10:12 ` [RFC/PATCH 00/14] perf record: Add support " Alexey Budankov
2019-02-04 10:36   ` Jiri Olsa
2019-02-04 11:29     ` Alexey Budankov
2019-02-04 11:41       ` Jiri Olsa
2019-02-04 18:56         ` Stephane Eranian
2019-02-04 19:27           ` Arnaldo Carvalho de Melo
2019-02-04 19:56             ` Alexey Budankov
2019-02-04 20:05             ` Stephane Eranian
2019-02-04 20:28               ` Jiri Olsa
2019-02-04 22:44                 ` Stephane Eranian [this message]
2019-02-05 13:37                   ` Jiri Olsa
2019-02-11 10:19                     ` Jiri Olsa
2019-02-11 18:34                       ` Stephane Eranian
2019-02-11 18:53                         ` Jiri Olsa
2019-02-11 19:32                           ` Arnaldo Carvalho de Melo
2019-02-11 20:18                             ` Jiri Olsa
2019-02-11 20:43                               ` Stephane Eranian
2019-02-14 11:34                                 ` Jiri Olsa
2019-02-14 12:57                                   ` Arnaldo Carvalho de Melo
2019-02-14 13:26                                     ` Jiri Olsa
2019-02-14 13:59                                       ` Arnaldo Carvalho de Melo
2019-02-14 21:30                                         ` Stephane Eranian
     [not found]                                           ` <CA+JHD90ssKi3CJ7yfCFTkrS8xwUsZhvd0t7cSCy1MF7TJ2XLYw@mail.gmail.com>
2019-02-14 21:39                                             ` Stephane Eranian
2019-02-11 18:55                         ` Arnaldo Carvalho de Melo
2019-02-11 19:30                           ` Stephane Eranian
2019-02-11 20:30                             ` Song Liu

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