linux-kernel - Re: [PATCH v2] perf util: Use target->per_thread and target->system

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Date:   Wed, 24 Jan 2018 08:28:42 +0100
From:   Jiri Olsa <jolsa@...hat.com>
To:     Jin Yao <yao.jin@...ux.intel.com>
Cc:     mathieu.poirier@...aro.org, acme@...nel.org, jolsa@...nel.org,
        peterz@...radead.org, mingo@...hat.com,
        alexander.shishkin@...ux.intel.com, Linux-kernel@...r.kernel.org,
        ak@...ux.intel.com, kan.liang@...el.com, yao.jin@...el.com
Subject: Re: [PATCH v2] perf util: Use target->per_thread and
 target->system_wide flags

On Wed, Jan 24, 2018 at 05:19:36PM +0800, Jin Yao wrote:
> Mathieu Poirier reports issue in commit ("73c0ca1eee3d perf thread_map:
> Enumerate all threads from /proc") that it has negative impact on
> 'perf record --per-thread'. It has the effect of creating a kernel event
> for each thread in the system for 'perf record --per-thread'.
> 
> Mathieu Poirier's patch ("perf util: Do not reuse target->per_thread flag")
> can fix this issue by creating a new target->all_threads flag.
> 
> This patch is based on Mathieu Poirier's patch but it doesn't use a new
> target->all_threads flag. This patch just uses 'target->per_thread &&
> target->system_wide' as a condition to check for all threads case.
> 
> v2:
> ---
> According to Jiri's comment, add description to explain why the patch
> uses 'target->per_thread && target->system_wide'.
> 
> v2 doesn't have functional change.

Acked-by: Jiri Olsa <jolsa@...nel.org>

thanks,
jirka