From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756459AbZETItm (ORCPT ); Wed, 20 May 2009 04:49:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752861AbZETItd (ORCPT ); Wed, 20 May 2009 04:49:33 -0400 Received: from mx2.redhat.com ([66.187.237.31]:54200 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751776AbZETItc (ORCPT ); Wed, 20 May 2009 04:49:32 -0400 Message-ID: <4A13C40B.8080608@redhat.com> Date: Wed, 20 May 2009 11:49:15 +0300 From: Avi Kivity User-Agent: Thunderbird 2.0.0.21 (X11/20090320) MIME-Version: 1.0 To: Peter Zijlstra CC: Mark Langsdorf , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH][KVM][retry 3] Add support for Pause Filtering to AMD SVM References: <200905050909.58583.mark.langsdorf@amd.com> <200905071000.14038.mark.langsdorf@amd.com> <200905081203.55484.mark.langsdorf@amd.com> <200905191356.37071.mark.langsdorf@amd.com> <1242806386.26820.549.camel@twins> <4A13C199.5020400@redhat.com> <1242808954.26820.556.camel@twins> In-Reply-To: <1242808954.26820.556.camel@twins> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Peter Zijlstra wrote: >>> That said, I still thoroughly dislike this whole approach. >>> >>> >> Can you explain why? We have a thread that has detected that it's >> spinning. Keeping on spinning is a waste of cpu time. Why not let >> something else use the cpu? >> > > Because its a polling interface. I much prefer it if we were to get a > wakeup notification when the vcpu holding the lock releases it. > It's a fully virtualized guest. There's no way to get this without patching the guest kernel. -- error compiling committee.c: too many arguments to function