From mboxrd@z Thu Jan 1 00:00:00 1970 From: Samuel Thibault Subject: Re: [Qemu-devel] [RFC][PATCH] Add HPET emulation to qemu (v2) Date: Sat, 2 Aug 2008 18:26:04 +0100 Message-ID: <20080802172604.GJ4535@implementation> References: <1217675114-17670-1-git-send-email-eak@us.ibm.com> <20080802113812.GD4535@implementation> <48947346.5080605@codemonkey.ws> <20080802172103.GH4535@implementation> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE To: Anthony Liguori , qemu-devel@nongnu.org, Beth Kon , Alexander Graf , kvm@vger.kernel.org Return-path: Received: from mtaout03-winn.ispmail.ntl.com ([81.103.221.49]:55315 "EHLO mtaout03-winn.ispmail.ntl.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751136AbYHBR0N (ORCPT ); Sat, 2 Aug 2008 13:26:13 -0400 Content-Disposition: inline In-Reply-To: <20080802172103.GH4535@implementation> Sender: kvm-owner@vger.kernel.org List-ID: Samuel Thibault, le Sat 02 Aug 2008 18:21:03 +0100, a =E9crit : > Anthony Liguori, le Sat 02 Aug 2008 09:46:30 -0500, a =E9crit : > > Samuel Thibault wrote: > > >Beth Kon, le Sat 02 Aug 2008 06:05:14 -0500, a =E9crit : > > > =20 > > >>I was trying to reproduce the wakeup every 10ms that=20 > > >>Samuel Thibault mentioned, thinking the HPET would improve it.=20 > > >>But for an idle guest in both cases (with and without HPET), the=20 > > >>number of wakeups per second was relatively low (28). > > >> =20 > > > > > >I was referring to vl.c's timeout =3D 10; which makes the select c= all > > >use a timeout of 10ms. That said, "/* If all cpus are halted then = wait > > >until the next IRQ */", so maybe that's why you get slower wakeups= per > > >second. I'm still surprised because of the call to qemu_mod_timer= in > > >pit_irq_timer_update which should setup at least a 100Hz timer wit= h > > >linux guests (when they don't have HPET available). > > > =20 > >=20 > > The patch disables that when hpet is active. >=20 > That's why I would expect, indeed, but he is reporting that _without_ what* > HPET he gets low wakeups per second already. Samuel