From mboxrd@z Thu Jan  1 00:00:00 1970
From: Jeremy Fitzhardinge <jeremy@goop.org>
Subject: Re: Xen spinlock questions
Date: Mon, 11 Aug 2008 11:10:06 -0700
Message-ID: <48A0807E.2030409@goop.org>
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	<C4BC9763.24F8E%keir.fraser@eu.citrix.com>
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To: Jan Beulich <jbeulich@novell.com>
Cc: xen-devel@lists.xensource.com, Keir Fraser <keir.fraser@eu.citrix.com>
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Jan Beulich wrote:
> Running kernel builds on 8 vCPU-s competing for 4 pCPU-s shows a 10%
> improvement in performance with the individual wakeup (patch attached
> - probably sub-optimal, but I didn't seem to be able to think of a lock-less
> mechanism to achieve the desired behavior), using ticket locks in the
> kernel.

What exactly are you measuring here?  Are you testing your 2.6.2x 
forward-port with an adaptation of pv spinlocks using ticket locks as 
the underlying locking mechanism?  Does the 10% improvement come 
compared to straightforward use of sched_poll, or compared to doing 
spurious wakeup detection?

    J