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


RE: [Xen-devel] [PATCH] softtsc for PV domains

To: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>, "Xen-Devel (E-mail)" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: RE: [Xen-devel] [PATCH] softtsc for PV domains
From: Dan Magenheimer <dan.magenheimer@xxxxxxxxxx>
Date: Thu, 27 Aug 2009 08:40:47 -0700 (PDT)
Delivery-date: Thu, 27 Aug 2009 08:41:35 -0700
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
In-reply-to: <C6BC1E53.13239%keir.fraser@xxxxxxxxxxxxx>
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>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
> > Attached patch implements softtsc (TSC emulation) for userland
> > code in PV domains.  It currently is tied to the existing
> > "softtsc" Xen boot option (which does the same thing but for
> > HVM domains).  Later it should be tied to a
> > vm.cfg option, but this is sufficient for now to obtain
> > performance degradation data for PV environments that
> > heavily utilize rdtsc.  To record emulation frequency,
> > additional output has been added to debug-key "t".
> Changeset 20128 is a fixed and simplified version of this. 
> Please take a
> look and test.
>  -- Keir


Looks good and seems to work.  I'm not sure why you wanted
to move the frequency info from the "t" debug key to the
new "s" debug key... and I'm a bit worried that since the "s"
key only registers if booted with softtsc, someone else will
use the "s" key for something else and cause a conflict
that won't be noticed until later.


Xen-devel mailing list

<Prev in Thread] Current Thread [Next in Thread>