From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH] KVM: Use thread debug register storage instead of kvm specific data Date: Tue, 01 Sep 2009 12:47:42 +0300 Message-ID: <4A9CEDBE.8010902@redhat.com> References: <1251798248-13164-1-git-send-email-avi@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org, Jan Kiszka To: Marcelo Tosatti , Andrew Theurer Return-path: Received: from mx1.redhat.com ([209.132.183.28]:40409 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753109AbZIAJwr (ORCPT ); Tue, 1 Sep 2009 05:52:47 -0400 In-Reply-To: <1251798248-13164-1-git-send-email-avi@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On 09/01/2009 12:44 PM, Avi Kivity wrote: > Instead of saving the debug registers from the processor to a kvm data > structure, rely in the debug registers stored in the thread structure. > This allows us not to save dr6 and dr7. > > Reduces lightweight vmexit cost by 350 cycles, or 11 percent. > Andrew, this is now available as the 'debugreg' branch of kvm.git. Given the massive performance improvement, it will be interesting to see how the test results change. Marcelo, please queue this for 2.6.32, and I think it's even suitable for -stable. -- error compiling committee.c: too many arguments to function