From mboxrd@z Thu Jan  1 00:00:00 1970
From: Thomas Gleixner <tglx@linutronix.de>
Subject: Re: Beginner's questions on userspace latency
Date: Fri, 22 Mar 2013 21:23:06 +0100 (CET)
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To: Oliver Nittka <oly@nittka.com>
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On Fri, 22 Mar 2013, Oliver Nittka wrote:
> The timing is fine most of the time, but putting the system under heavy
> CPU and USB load leads to occasional glitches where the time between two
> ioctl calls can be as high as 50ms.

The kernel tracer is your friend. Enable the kernel function tracer
and add a check into your application which detects the issue and then
stops the trace. See the cyclictest source code for an example how to
do that.

Thanks,

	tglx