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Subject: RE: [PATCH] perf_counter: Fix a race on perf_counter_ctx
From: Peter Zijlstra <peterz@infradead.org>
To: "Metzger, Markus T" <markus.t.metzger@intel.com>
Cc: Ingo Molnar <mingo@elte.hu>, "tglx@linutronix.de" <tglx@linutronix.de>,
       "hpa@zytor.com" <hpa@zytor.com>,
       "markus.t.metzger@gmail.com" <markus.t.metzger@gmail.com>,
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       Paul Mackerras <paulus@samba.org>
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Date: Tue, 18 Aug 2009 14:59:45 +0200
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On Tue, 2009-08-18 at 14:59 +0200, Peter Zijlstra wrote:
> On Tue, 2009-08-18 at 13:49 +0100, Metzger, Markus T wrote:
> > Hi Ingo, Peter,
> > 
> > Did you say that branch tracing is working for you?
> > 
> > On my system, the kernel hangs.
> > 
> > Could it be that it simply takes too long to copy the trace? When I set the number
> > of samples to 10, everything seems to work OK. When I increase that number to 1000,
> > the kernel is getting very slow and eventually hangs.
> > 
> > I get a message "hrtimer: interrupt too slow", and I get a soft lockup bug. The rest
> > of the message log seems pretty garbled.

How many NMI/s is this generating anyway?