linux-kernel - Re: [PATCH 08/22] perf daemon: Add config file change check

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Date:   Tue, 19 Jan 2021 14:31:55 +0900
From:   Namhyung Kim <namhyung@...nel.org>
To:     Jiri Olsa <jolsa@...nel.org>
Cc:     Arnaldo Carvalho de Melo <acme@...nel.org>,
        lkml <linux-kernel@...r.kernel.org>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Ingo Molnar <mingo@...nel.org>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Michael Petlan <mpetlan@...hat.com>,
        Ian Rogers <irogers@...gle.com>,
        Stephane Eranian <eranian@...gle.com>,
        Alexei Budankov <abudankov@...wei.com>
Subject: Re: [PATCH 08/22] perf daemon: Add config file change check

On Sun, Jan 3, 2021 at 7:05 AM Jiri Olsa <jolsa@...nel.org> wrote:
>
> Adding support to detect daemon's config file changes
> and re-read the configuration when that happens.

Hmm.. maybe some of the code in the previous commit can be moved here.

Thanks,
Namhyung

>
> Using inotify file descriptor pluged into the main
> fdarray object for polling.
>
> Example:
>
>   # cat ~/.perfconfig
>   [daemon]
>   base=/opt/perfdata
>
>   [session-cycles]
>   run = -m 10M -e cycles --overwrite --switch-output -a
>
> Starting the daemon:
>
>   # perf daemon start
>
> Check sessions:
>
>   # perf daemon
>   [772262:daemon] base: /opt/perfdata
>   [772263:cycles] perf record -m 10M -e cycles --overwrite --switch-output -a
>
> Change '-m 10M' to '-m 20M', and check daemon log:
>
>   # tail -f /opt/perfdata/output
>   [2021-01-02 20:31:41.234045] daemon started (pid 772262)
>   [2021-01-02 20:31:41.235072] reconfig: ruining session [cycles:772263]: -m 10M -e cycles --overwrite --switch-output -a
>   [2021-01-02 20:32:08.310137] reconfig: session 'cycles' killed
>   [2021-01-02 20:32:08.310847] reconfig: ruining session [cycles:772338]: -m 20M -e cycles --overwrite --switch-output -a
>
> And the session list:
>
>   # perf daemon
>   [772262:daemon] base: /opt/perfdata
>   [772338:cycles] perf record -m 20M -e cycles --overwrite --switch-output -a
>
> Note the changed '-m 20M' option is in place.
>
> Signed-off-by: Jiri Olsa <jolsa@...nel.org>
> ---