Subject: Re: 2.6.24-rc8-rt1: Strange latencies on mpc5200 powerpc
From: Daniel Walker <dwalker@mvista.com>
To: Luotao Fu <l.fu@pengutronix.de>
Cc: Steven Rostedt <rostedt@goodmis.org>,
       Wolfgang Grandegger <wg@grandegger.com>,
       LKML <linux-kernel@vger.kernel.org>,
       RT <linux-rt-users@vger.kernel.org>, Ingo Molnar <mingo@elte.hu>,
       Thomas Gleixner <tglx@linutronix.de>
In-Reply-To: <20080123145340.GE6200@pengutronix.de>
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	 <478F2A46.5070506@grandegger.com>  <20080123145340.GE6200@pengutronix.de>
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Date: Wed, 23 Jan 2008 07:50:19 -0800
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On Wed, 2008-01-23 at 15:53 +0100, Luotao Fu wrote:

> I was doing some tests on my mpc5200b Board to reproduce the high latency as
> measured by wolfgang.
> 
> I ran some tests with 
> while [ 1 ]; do ls /bin;done
> as non-rt workload, as in Wolfgangs Scenario.
> 

Can you try enabling CRITICAL_PREEMPT_TIMING only, and not latency
tracing .. You won't get a trace, but you will get some indication of
the start/stop points of the latency if it's preempt latency, and a
measurement of the longest latency..

Daniel

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