Re: [PATCH 00/10] perf tools: Use SIGUSR2 control data dumpping

[Jiri Olsa]

On Wed, Apr 13, 2016 at 08:21:03AM +0000, Wang Nan wrote:
> This patch set is a preparation to support overwritable ring buffer.
> However, even without the kernel side core patch [1] is accept this
> patch set is still useful.
> 
> With this patch set, perf switches output when receiving SIGUSR2. For
> example:
> 
>  # perf record -a -F99 --switch-output &
>  [1] 26435
>  # kill -s SIGUSR2 26435
>  [ perf record: dump data: Woken up 1 times ]
>  # [ perf record: Dump perf.data.2016041323544373 ]
>  # kill -s SIGUSR2 26435
>  [ perf record: dump data: Woken up 1 times ]
>  # [ perf record: Dump perf.data.2016041323544730 ]
>  # fg
>  perf record -a -F99 --switch-output
>  ^C[ perf record: Woken up 1 times to write data ]
>  [ perf record: Dump perf.data.2016041323545019 ]
>  [ perf record: Captured and wrote 0.395 MB perf.data.<timestamp> ]
> 
> User can periodically generates perf trace with a simple script, then
> remove most of them, only keeps scripts collected when something
> unusual is detected.
> 
> After [1], perf can be totally silent before receiving SIGUSR2. Trace
> is collected in kernel overwritable ring buffer, and dumpped when
> SIGUSR2 is received.
> 
> [1] http://lkml.kernel.org/r/1459865478-53413-1-git-send-email-wangnan0@xxxxxxxxxx
> 
> Cc: Wang Nan <wangnan0@xxxxxxxxxx>
> Cc: He Kuang <hekuang@xxxxxxxxxx>
> Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
> Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
> Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
> Cc: Zefan Li <lizefan@xxxxxxxxxx>
> Cc: pi3orama@xxxxxxx
> 
> Wang Nan (10):
>   perf tools: Make ordered_events reusable
>   perf tools: Add perf_data_file__switch() helper
>   perf record: Turns auxtrace_snapshot_enable into 3 states
>   perf record: Add '--timestamp-filename' option to append timestamp to
>     output filename
>   perf record: Split output into multiple files via '--switch-output'
>   perf record: Force enable --timestamp-filename when --switch-output is
>     provided
>   perf record: Disable buildid cache options by default in switch output
>     mode
>   perf record: Re-synthesize tracking events after output switching
>   perf record: Generate tracking events for process forked by perf
>   perf core: Add backward attribute to perf event

I did not get 3/10 patch and the patchset did not apply cleanly,
git am failed.. would you have it in a branch somewhere?

thanks,
jirka