linux-kernel - Re: [PATCH 3/3] function-graph: ignore times across schedule

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Message-ID: <20090324135833.GB32043@elte.hu>
Date:	Tue, 24 Mar 2009 14:58:33 +0100
From:	Ingo Molnar <mingo@...e.hu>
To:	Steven Rostedt <rostedt@...dmis.org>
Cc:	linux-kernel@...r.kernel.org,
	Andrew Morton <akpm@...ux-foundation.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Steven Rostedt <srostedt@...hat.com>
Subject: Re: [PATCH 3/3] function-graph: ignore times across schedule

* Steven Rostedt <rostedt@...dmis.org> wrote:

> From: Steven Rostedt <srostedt@...hat.com>
> 
> Impact: more accurate timings
> 
> The current method of function graph tracing does not take into
> account the time spent when a task is not running. This shows functions
> that call schedule have increased costs:
> 
>  3) + 18.664 us   |      }
>  ------------------------------------------
>  3)    <idle>-0    =>  kblockd-123
>  ------------------------------------------
> 
>  3)               |      finish_task_switch() {
>  3)   1.441 us    |        _spin_unlock_irq();
>  3)   3.966 us    |      }
>  3) ! 2959.433 us |    }
>  3) ! 2961.465 us |  }

dunno - i actually like how it shows the _real_ elapsed time. Why is 
this wrong?

	Ingo
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