Date: Wed, 14 Jan 2009 09:06:40 +0100
From: Ingo Molnar <mingo@elte.hu>
To: Mandeep Singh Baines <msb@google.com>
Cc: linux-kernel@vger.kernel.org, rientjes@google.com, mbligh@google.com,
       thockin@google.com, akpm@linux-foundation.org, netdev@vger.kernel.org
Subject: Re: [PATCH] softlockup: detect bottom-half lockups
Message-ID: <20090114080640.GA19116@elte.hu>
References: <20090114070447.GA25222@google.com>
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* Mandeep Singh Baines <msb@google.com> wrote:

> The feature should be useful to real-time developers and developers of 
> network and other high-performance drivers.

hm, did you know about the ftrace latency tracers:

 config IRQSOFF_TRACER
         bool "Interrupts-off Latency Tracer"

 config PREEMPT_TRACER
         bool "Preemption-off Latency Tracer"

 config SCHED_TRACER
         bool "Scheduling Latency Tracer"

PREEMPT_TRACER would have shown you that softirqs-off section very nicely. 

(And if you also enable the function tracer then not just the latency 
endpoint is shown, but also all the function calls that happened in the 
critical section.)

	Ingo
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