From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: Make QEmu HPET disabled by default for KVM? Date: Thu, 11 Mar 2010 10:28:12 +0200 Message-ID: <4B98A99C.8020909@redhat.com> References: <201003111552.54293.sheng@linux.intel.com> <4B98A294.7010104@redhat.com> <201003111623.58755.sheng@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Marcelo Tosatti , kvm@vger.kernel.org To: Sheng Yang Return-path: Received: from mx1.redhat.com ([209.132.183.28]:32647 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751910Ab0CKI2O (ORCPT ); Thu, 11 Mar 2010 03:28:14 -0500 In-Reply-To: <201003111623.58755.sheng@linux.intel.com> Sender: kvm-owner@vger.kernel.org List-ID: On 03/11/2010 10:23 AM, Sheng Yang wrote: >>> I have kept --no-hpet in my setup for >>> months... >>> >> Any details about the problems? HPET is important to some guests. >> >> > Seems like HPET reaction is too slow to satisfy some guests(for it would > replace PIT). > > Here is the thread last time. > > http://thread.gmane.org/gmane.comp.emulators.kvm.devel/44899 > > Thanks. We can address this in three ways: first, adjust the guest not to do timing related tests when virtualized (since no matter what we do, the tests may fail). Second, I think we should implement userspace ack notifiers (similar to tpr access notifiers already present). Third, we can implement a kernel hpet, which, after we solve the zillion bug it introduces, will also give a nice performance improvement for hpet intensive workloads. -- error compiling committee.c: too many arguments to function