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SubjectRe: [PATCH 14/14] perf record: Add --dir option to store data in directory
On Tue, Feb 05, 2019 at 03:36:24PM +0300, Alexey Budankov wrote:
>
> On 03.02.2019 18:30, Jiri Olsa wrote:
> > Adding --dir option to store data in directory. It's next
> > step for multiple threads in record. It's not possible
> > to make directory data via --dir option, like:
> >
> > $ perf record --dir perf bench sched messaging
> > $ ls -l perf.data
> > total 344
> > -rw-------. 1 jolsa jolsa 43864 Jan 20 22:26 data.0
> > -rw-------. 1 jolsa jolsa 30464 Jan 20 22:26 data.1
> > -rw-------. 1 jolsa jolsa 53816 Jan 20 22:26 data.2
> > -rw-------. 1 jolsa jolsa 30368 Jan 20 22:26 data.3
> > -rw-------. 1 jolsa jolsa 40088 Jan 20 22:26 data.4
> > -rw-------. 1 jolsa jolsa 42592 Jan 20 22:26 data.5
> > -rw-------. 1 jolsa jolsa 56136 Jan 20 22:26 data.6
> > -rw-------. 1 jolsa jolsa 25992 Jan 20 22:26 data.7
> > -rw-------. 1 jolsa jolsa 8832 Jan 20 22:26 header
> >
> > There's a data file created for every cpu and it's storing
> > data for those cpu maps.
> >
> > It's possible to transform directory data into standard
> > perf.data file via following inject command:
> >
> > $ perf inject -o perf.data.file -i perf.data
> >
> > Link: http://lkml.kernel.org/n/tip-0kjm8wpglzu2tm18tpagfm4d@git.kernel.org
> > Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> > ---
> > tools/perf/Documentation/perf-record.txt | 3 ++
> > tools/perf/builtin-record.c | 59 ++++++++++++++++++++++--
> > tools/perf/util/mmap.h | 23 ++++-----
> > 3 files changed, 70 insertions(+), 15 deletions(-)
> >
> > diff --git a/tools/perf/Documentation/perf-record.txt b/tools/perf/Documentation/perf-record.txt
> > index d232b13ea713..8dcdc8cabcad 100644
> > --- a/tools/perf/Documentation/perf-record.txt
> > +++ b/tools/perf/Documentation/perf-record.txt
> > @@ -505,6 +505,9 @@ config terms. For example: 'cycles/overwrite/' and 'instructions/no-overwrite/'.
> >
> > Implies --tail-synthesize.
> >
> > +--dir::
> > +Store data into directory with one data file for cpu.
> > +
>
> Makes sense to mention compatibility with -o option and per-thread buffer mapping.

right, will do

>
> > SEE ALSO
> > --------
> > linkperf:perf-stat[1], linkperf:perf-list[1]
> > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c
> > index cd02ab3ec4ff..87e39b9cc7bd 100644
> > --- a/tools/perf/builtin-record.c
> > +++ b/tools/perf/builtin-record.c
> > @@ -111,17 +111,21 @@ static bool switch_output_time(struct record *rec)
> > trigger_is_ready(&switch_output_trigger);
> > }
> >
> > -static int record__write(struct record *rec, struct perf_mmap *map __maybe_unused,
> > +static int record__write(struct record *rec, struct perf_mmap *map,
> > void *bf, size_t size)
> > {
> > - struct perf_data_file *file = &rec->session->data->file;
> > + struct perf_data_file *file = &rec->data.file;
> > +
> > + if (map && map->file)
> > + file = map->file;
>
> For AIO mode per-cpu streaming could be done in parallel because Posix
> AIO API uses a separate thread for every open data.# or header fd.

yes, I was thinking of that and I plan to try that to see
if there's some benefit

>
> >
> > if (perf_data_file__write(file, bf, size) < 0) {
> > pr_err("failed to write perf data, error: %m\n");
> > return -1;
> > }
> >
> > - rec->bytes_written += size;
> > + if (file == &rec->data.file)
> > + rec->bytes_written += size;
>
> switch-output logic now tracks header file size only?
> If so, it probably needs to be corrected or simply disabled
> for --output_dir mode.

the rec->bytes_written value is used to track header file size,
which is used to fill in the header data section in here
record__finish_output, we can't mix other file sizes into it

the switch-output option still needs some changes to work
over the directory data

jirka

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