From mboxrd@z Thu Jan 1 00:00:00 1970 From: Keir Fraser Subject: Re: [PATCH 0/2] Improve hpet accuracy Date: Mon, 09 Jun 2008 08:36:17 +0100 Message-ID: References: Mime-Version: 1.0 Content-Type: multipart/mixed; boundary="===============1239341038==" Return-path: In-Reply-To: List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Mime-version: 1.0 Sender: xen-devel-bounces@lists.xensource.com Errors-To: xen-devel-bounces@lists.xensource.com To: Dave Winchell , dan.magenheimer@oracle.com Cc: xen-devel , Ben Guthro List-Id: xen-devel@lists.xenproject.org > This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible. --===============1239341038== Content-type: multipart/alternative; boundary="B_3295845381_17207748" > This message is in MIME format. Since your mail reader does not understand this format, some or all of this message may not be legible. --B_3295845381_17207748 Content-type: text/plain; charset="ISO-8859-1" Content-transfer-encoding: quoted-printable On 9/6/08 00:26, "Dave Winchell" wrote: >> > 4) config file parameters >=20 > Hpet enabled. Timer_mode set to HVM_HPET_guest_computes_missed_ticks > for all Linux guests and to HVM_HPET_guest_does_not_compute_missed_ticks > for Windows 2k8-64 and Vista 64. > 8 vcpus for Linux and 2 for Windows. These new HVM_HPET options seems a weird design choice. It appears that you can only set these or one of the old options, so there=B9s not actually any independence between the mode used by vpt.c and the mode used by hpet.c. At guest install time you ought to be able to tell whether the guest will use hpet or not based on its version (RHELx, SLESy, Winz etc etc) and decide whether missed-ticks accounting is required or not. I=B9d be more agreeable to a partch that stripped out the physical hpet accesses (since you say they are not the reason for the improvement in accuracy), built hpet on top of vpt, and added the necessary extra mechanisms to deal with interrupt broadcasts into vpt.c. And which was spli= t into more separate pieces of mechanism. -- Keir --B_3295845381_17207748 Content-type: text/html; charset="ISO-8859-1" Content-transfer-encoding: quoted-printable Re: [Xen-devel] [PATCH 0/2] Improve hpet accuracy On 9/= 6/08 00:26, "Dave Winchell" <dwinchell@virtualiron.com> wrot= e:

> 4) config file parameters

Hpet enabled. Timer_mode set to HVM_HPET_guest_computes_missed_ticks
for all Linux guests and to HVM_HPET_guest_does_not_compute_missed_ticks for Windows 2k8-64 and Vista 64.
8 vcpus for Linux and 2 for Windows.

These new HVM_HPET options seems a weird design choice. It appears that you= can only set these or one of the old options, so there’s not a= ctually any independence between the mode used by vpt.c and the mode used by= hpet.c. At guest install time you ought to be able to tell whether the gues= t will use hpet or not based on its version (RHELx, SLESy, Winz etc etc) and= decide whether missed-ticks accounting is required or not.

I’d be more agreeable to a partch that stripped out the physical hpet= accesses (since you say they are not the reason for the improvement in accu= racy), built hpet on top of vpt, and added the necessary extra mechanisms to= deal with interrupt broadcasts into vpt.c. And which was split into more se= parate pieces of mechanism.

 -- Keir
 --B_3295845381_17207748-- --===============1239341038== Content-Type: text/plain; charset="us-ascii" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Content-Disposition: inline _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel --===============1239341038==--