From: David Ahern <dsahern@gmail.com>
To: Namhyung Kim <namhyung@kernel.org>
Cc: Arnaldo Melo <acme@ghostprotocols.net>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Ingo Molnar <mingo@kernel.org>,
Frederic Weisbecker <fweisbec@gmail.com>,
Peter Zijlstra <a.p.zijlstra@chello.nl>,
Mike Galbraith <efault@gmx.de>, Jiri Olsa <jolsa@redhat.com>,
Stephane Eranian <eranian@google.com>,
Pekka Enberg <penberg@kernel.org>
Subject: Re: [PATCH 6/8] perf sched: Introduce timehist command
Date: Thu, 28 Nov 2013 18:58:46 -0700 [thread overview]
Message-ID: <5297F4D6.3070408@gmail.com> (raw)
In-Reply-To: <87k3fsowwe.fsf@sejong.aot.lge.com>
On 11/28/13, 5:48 PM, Namhyung Kim wrote:
> Do we really need to look up the callchain to find out an idle thread?
>
> $ perf sched script | grep swapper | head
> swapper 0 [001] 4294177.326996: sched:sched_switch: prev_comm=swapper/1 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=Xorg next_pid=1094 next_prio=120
> swapper 0 [010] 4294177.327019: sched:sched_switch: prev_comm=swapper/10 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=perf next_pid=13902 next_prio=120
> perf 13901 [002] 4294177.327074: sched:sched_switch: prev_comm=perf prev_pid=13901 prev_prio=120 prev_state=S ==> next_comm=swapper/2 next_pid=0 next_prio=120
> swapper 0 [004] 4294177.327096: sched:sched_switch: prev_comm=swapper/4 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=synergys next_pid=1521 next_prio=120
> swapper 0 [000] 4294177.327102: sched:sched_switch: prev_comm=swapper/0 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=gnome-terminal next_pid=2392 next_prio=120
> Xorg 1094 [001] 4294177.327112: sched:sched_switch: prev_comm=Xorg prev_pid=1094 prev_prio=120 prev_state=S ==> next_comm=swapper/1 next_pid=0 next_prio=120
> swapper 0 [007] 4294177.327122: sched:sched_switch: prev_comm=swapper/7 prev_pid=0 prev_prio=120 prev_state=R ==> next_comm=perf next_pid=13902 next_prio=120
> migration/10 58 [010] 4294177.327124: sched:sched_switch: prev_comm=migration/10 prev_pid=58 prev_prio=0 prev_state=S ==> next_comm=swapper/10 next_pid=0 next_prio=120
> synergys 1521 [004] 4294177.327144: sched:sched_switch: prev_comm=synergys prev_pid=1521 prev_prio=120 prev_state=S ==> next_comm=swapper/4 next_pid=0 next_prio=120
> gnome-terminal 2392 [000] 4294177.327286: sched:sched_switch: prev_comm=gnome-terminal prev_pid=2392 prev_prio=120 prev_state=S ==> next_comm=swapper/0 next_pid=0 next_prio=120
>
> It seems every idle/swapper thread for each cpu has a pid of 0.
The command was developed using context-switch events. Try the next
patch and use:
perf record -e cs -c 1 -ag
perf sched timehist
David
next prev parent reply other threads:[~2013-11-29 1:58 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-11-18 20:32 [PATCH 0/8] perf: sched timehist command David Ahern
2013-11-18 20:32 ` [PATCH 1/8] perf tool: Skip ignored symbols while printing callchain David Ahern
2013-11-30 12:52 ` [tip:perf/core] perf evsel: " tip-bot for David Ahern
2013-11-18 20:32 ` [PATCH 2/8] perf symbols: Move idle syms check from top to generic function David Ahern
2013-11-28 8:36 ` Namhyung Kim
2013-11-30 15:58 ` David Ahern
2013-11-30 12:52 ` [tip:perf/core] " tip-bot for David Ahern
2013-11-18 20:32 ` [PATCH 3/8] perf symbol: Save vmlinux or kallsyms path loaded David Ahern
2013-11-22 18:44 ` Arnaldo Carvalho de Melo
2013-11-22 19:13 ` David Ahern
2013-11-22 19:40 ` Arnaldo Carvalho de Melo
2013-11-22 20:09 ` David Ahern
2013-11-18 20:32 ` [PATCH 4/8] perf thread: Move comm_list check into function David Ahern
2013-11-30 12:52 ` [tip:perf/core] " tip-bot for David Ahern
2013-11-18 20:32 ` [PATCH 5/8] perf tool: export setup_list David Ahern
2013-11-28 8:45 ` Namhyung Kim
2013-11-30 12:52 ` [tip:perf/core] perf tools: Export setup_list tip-bot for David Ahern
2013-11-18 20:32 ` [PATCH 6/8] perf sched: Introduce timehist command David Ahern
2013-11-28 9:50 ` Namhyung Kim
2013-11-28 16:01 ` David Ahern
2013-11-28 15:38 ` Namhyung Kim
2013-11-28 16:01 ` David Ahern
2013-11-29 0:48 ` Namhyung Kim
2013-11-29 1:58 ` David Ahern [this message]
2013-12-04 4:15 ` David Ahern
2013-11-18 20:32 ` [PATCH 7/8] perf sched timehist: Add support for context-switch event David Ahern
2013-11-18 20:32 ` [PATCH 8/8] perf sched : Add documentation for timehist options David Ahern
2013-11-28 15:42 ` Namhyung Kim
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