linux-kernel - Re: [PATCH perf/urgent] perf top: Always sample time

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Date:   Mon, 15 Apr 2019 14:22:15 -0300
From:   Arnaldo Carvalho de Melo <arnaldo.melo@...il.com>
To:     Jiri Olsa <jolsa@...nel.org>
Cc:     lkml <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Peter Zijlstra <a.p.zijlstra@...llo.nl>,
        Bastian Beischer <bastian.beischer@...h-aachen.de>
Subject: Re: [PATCH perf/urgent] perf top: Always sample time

Em Mon, Apr 15, 2019 at 02:53:33PM +0200, Jiri Olsa escreveu:
> Bastian reported broken perf top -p PID command, it won't
> display any data.
> 
> The problem is that for -p option we monitor single thread,
> so we don't enable time in samples, because it's not needed.
> 
> However since commit 16c66bc167cc we use ordered queues to
> stash data plus later commits added logic for dropping samples
> in case there's big load and we don't keep up. All this needs
> timestamp for sample. Enabling it unconditionally for perf top.

Thanks, tested and applied.

- Arnaldo
 
> Fixes: 16c66bc167cc ("perf top: Add processing thread")
> Reported-by: Bastian Beischer <bastian.beischer@...h-aachen.de>
> Link: http://lkml.kernel.org/n/tip-zhn7jg8hqpl9547g7vqjini7@git.kernel.org
> Signed-off-by: Jiri Olsa <jolsa@...nel.org>
> ---
>  tools/perf/builtin-top.c | 1 +
>  1 file changed, 1 insertion(+)
> 
> diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
> index 1999d6533d12..fbbb0da43abb 100644
> --- a/tools/perf/builtin-top.c
> +++ b/tools/perf/builtin-top.c
> @@ -1377,6 +1377,7 @@ int cmd_top(int argc, const char **argv)
>  			 * */
>  			.overwrite	= 0,
>  			.sample_time	= true,
> +			.sample_time_set = true,
>  		},
>  		.max_stack	     = sysctl__max_stack(),
>  		.annotation_opts     = annotation__default_options,
> -- 
> 2.17.2

-- 

- Arnaldo