From: Jeremy Fitzhardinge <jeremy@goop.org>
To: James Harper <james.harper@bendigoit.com.au>
Cc: George Dunlap <George.Dunlap@eu.citrix.com>,
Juergen Gross <juergen.gross@fujitsu-siemens.com>,
Keir Fraser <keir.fraser@eu.citrix.com>,
xen-devel@lists.xensource.com, Venefax <venefax@gmail.com>
Subject: Re: [Patch 2 of 2]: PV-domain SMP performance Linux-part
Date: Fri, 16 Jan 2009 09:43:34 -0800 [thread overview]
Message-ID: <4970C746.7000101@goop.org> (raw)
In-Reply-To: <AEC6C66638C05B468B556EA548C1A77D015503BC@trantor>
James Harper wrote:
> Do you think your changes could be applicable to HVM domains with
> appropriately patched kernel spinlock routines?
>
> I had previously wondered about optimizing spinlocks, my idea was
> basically for Xen to set a bit in a structure to indicate what vcpus are
> currently scheduled, and my modified spinlock acquire routine would
> check if the current vcpu wants a spinlock that is held by a currently
> unscheduled vcpu, and if so yield to Xen to let the other vcpu schedule.
>
> The only thing I would need from Xen is to know which vcpus were
> currently scheduled, the rest would be DomU based.
>
In a PV domain you can already get that information from the
runstate_info structure, which can be mapped into the domain's memory
and just read directly. I don't know if its available to an hvm domain,
but I don't think it would be hard to implement if it isn't.
J
next prev parent reply other threads:[~2009-01-16 17:43 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-12-17 12:22 [Patch 2 of 2]: PV-domain SMP performance Linux-part Juergen Gross
2008-12-17 15:06 ` Jan Beulich
2008-12-18 7:18 ` Juergen Gross
2008-12-18 7:41 ` Jan Beulich
2008-12-19 8:12 ` Juergen Gross
2008-12-19 9:10 ` Keir Fraser
2008-12-19 9:25 ` Juergen Gross
2008-12-19 9:56 ` Keir Fraser
2009-01-16 7:16 ` Juergen Gross
2009-01-16 7:38 ` Venefax
2009-01-16 7:48 ` Juergen Gross
2009-01-16 7:57 ` Venefax
2009-01-16 8:19 ` Juergen Gross
2009-01-16 10:16 ` James Harper
2009-01-16 10:31 ` Juergen Gross
2009-01-16 10:41 ` Keir Fraser
2009-01-16 11:01 ` James Harper
2009-01-16 11:14 ` Keir Fraser
2009-01-16 11:18 ` Jan Beulich
2009-01-16 14:40 ` Steve Prochniak
2009-01-16 17:43 ` Jeremy Fitzhardinge [this message]
2009-01-16 8:17 ` Keir Fraser
2009-01-16 9:36 ` Juergen Gross
2009-01-16 9:53 ` Keir Fraser
2009-01-16 17:41 ` Jeremy Fitzhardinge
2009-01-19 17:15 ` George Dunlap
2009-01-20 20:12 ` Jeremy Fitzhardinge
2008-12-19 9:33 ` Jan Beulich
2008-12-19 9:56 ` Keir Fraser
2008-12-19 15:15 ` George Dunlap
2009-01-12 12:55 ` Juergen Gross
2009-01-19 17:32 ` George Dunlap
2009-01-20 7:56 ` Juergen Gross
2008-12-19 10:06 ` Juergen Gross
2008-12-19 10:36 ` Jan Beulich
2008-12-19 10:42 ` Juergen Gross
2008-12-19 10:48 ` Juergen Gross
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