linux-kernel - Re: [PATCH 00/20] x86: ticket lock rewrite and paravirtualization

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Message-ID: <1289855312.2109.555.camel@laptop>
Date:	Mon, 15 Nov 2010 22:08:32 +0100
From:	Peter Zijlstra <peterz@...radead.org>
To:	Jeremy Fitzhardinge <jeremy@...p.org>
Cc:	"H. Peter Anvin" <hpa@...or.com>,
	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	Jan Beulich <JBeulich@...ell.com>, Avi Kivity <avi@...hat.com>,
	Xen-devel <xen-devel@...ts.xensource.com>,
	Linux Virtualization <virtualization@...ts.linux-foundation.org>,
	Srivatsa Vaddagiri <vatsa@...ux.vnet.ibm.com>,
	Mathieu Desnoyers <mathieu.desnoyers@...ymtl.ca>
Subject: Re: [PATCH 00/20] x86: ticket lock rewrite and paravirtualization

On Mon, 2010-11-15 at 13:02 -0800, Jeremy Fitzhardinge wrote:
> 
> As a heuristic, it shouldn't be too bad performancewise, since
> (handwaving) if ticketholder N has entered the slowpath, then its likely
> that N+1 will as well. 

Yes, esp. if the whole slow unlock path takes more cycles than you spin
for to begin with.

I think this approach is definitely worth trying.
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