linux-kernel - Re: [RFC GIT PULL] perf/trace/lock optimization/scalability improvements

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Date:	Thu, 4 Feb 2010 20:40:47 +0100
From:	Jens Axboe <jens.axboe@...cle.com>
To:	Frederic Weisbecker <fweisbec@...il.com>
Cc:	Ingo Molnar <mingo@...e.hu>, LKML <linux-kernel@...r.kernel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Steven Rostedt <rostedt@...dmis.org>,
	Paul Mackerras <paulus@...ba.org>,
	Hitoshi Mitake <mitake@....info.waseda.ac.jp>,
	Li Zefan <lizf@...fujitsu.com>,
	Lai Jiangshan <laijs@...fujitsu.com>,
	Masami Hiramatsu <mhiramat@...hat.com>
Subject: Re: [RFC GIT PULL] perf/trace/lock optimization/scalability
	improvements

On Wed, Feb 03 2010, Frederic Weisbecker wrote:
> Ok, thanks a lot, the fact you can test on a 64 threads box is critically
> helpful.
> 
> I also wonder what happens after this patch applied:
> 
> diff --git a/kernel/perf_event.c b/kernel/perf_event.c
> index 98fd360..254b3d4 100644
> --- a/kernel/perf_event.c
> +++ b/kernel/perf_event.c
> @@ -3094,7 +3094,8 @@ static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
>         if (event->parent)
>                 event = event->parent;
>  
> -       return task_pid_nr_ns(p, event->ns);
> +       return p->pid;
>  }
> 
> In my box it has increased the speed from 2x this patchset.

Doesn't seem to change anything, same runtime for a ls.

> I wonder if the tool becomes usable for you with that.
> Otherwise, it means we have other things to fix, and
> the result of:
> 
> 	perf record -g -f perf lock record sleep 6
> 	perf report
> 
> would be very nice to have.

root@...alem:/dev/shm # perf record -g -f perf lock record sleep 6
[ perf record: Woken up 0 times to write data ]
[ perf record: Captured and wrote 446.208 MB perf.data (~19495127 samples) ]
[ perf record: Woken up 9 times to write data ]
[ perf record: Captured and wrote 1.135 MB perf.data (~49609 samples) ]

It's huuuge. Thankfully the output isn't so big, I've attached it.

-- 
Jens Axboe


View attachment "perf-lock-report.txt" of type "text/plain" (34652 bytes)