Message-ID: <50A264C6.4010906@redhat.com>
Date: Tue, 13 Nov 2012 10:18:30 -0500
From: Prarit Bhargava <prarit@redhat.com>
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To: John Stultz <johnstul@us.ibm.com>
CC: paulmck@linux.vnet.ibm.com, Linux Kernel <linux-kernel@vger.kernel.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Marcelo Tosatti <mtosatti@redhat.com>
Subject: Re: RCU NOHZ, tsc, and clock_gettime
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On 11/12/2012 06:27 PM, John Stultz wrote:

> Hey Prarit,
>     Just back from being on leave, and wanted to check in on this. Did you ever
> get to run with an increase sample size to see how that affected things?  Its
> exactly your point that the non-NOHZ case could align the execution of a short
> run in a way that you always see good results, where as with NOHZ the alignment
> might not be the same, so you see periodic delays from timer interrupts, etc.
> 
> Anyway, let me know if this got resolved or not.

Hey John,

I never did narrow this down, although this "disappears" with the move to the
lower resolution patches in upstream.  I have not, however, done any testing to
see if the situation is actually resolved or if we just reduced the problem by a
factor of 1000 ;)

P.
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