This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
Home Products Support Community News


[Xen-devel] Re: [PATCH 00/20] x86: ticket lock rewrite and paravirtualiz

To: Jeremy Fitzhardinge <jeremy@xxxxxxxx>
Subject: [Xen-devel] Re: [PATCH 00/20] x86: ticket lock rewrite and paravirtualization
From: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Date: Mon, 15 Nov 2010 22:08:32 +0100
Cc: Xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>, Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxx>, Srivatsa, Linux, Linux Kernel Mailing List <linux-kernel@xxxxxxxxxxxxxxx>, Jan Beulich <JBeulich@xxxxxxxxxx>, Virtualization <virtualization@xxxxxxxxxxxxxxxxxxxxxxxxxx>, Vaddagiri <vatsa@xxxxxxxxxxxxxxxxxx>, Kivity <avi@xxxxxxxxxx>, "H. Peter Anvin" <hpa@xxxxxxxxx>, Avi
Delivery-date: Mon, 15 Nov 2010 13:11:22 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <4CE19FD1.2000804@xxxxxxxx>
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
References: <cover.1288794124.git.jeremy.fitzhardinge@xxxxxxxxxx> <4CDDBBD3.5050903@xxxxxxxxx> <4CDDBCE4.80906@xxxxxxxx> <4CDDBDB5.8000800@xxxxxxxxx> <4CE1915F.60507@xxxxxxxx> <4CE1920F.5000509@xxxxxxxxx> <1289852088.2109.553.camel@laptop> <4CE19FD1.2000804@xxxxxxxx>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
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.

Xen-devel mailing list