From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH][retry 3] Add support for Pause Filtering to AMD SVM Date: Wed, 20 May 2009 11:49:15 +0300 Message-ID: <4A13C40B.8080608@redhat.com> 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> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Mark Langsdorf , Joerg Roedel , kvm@vger.kernel.org, linux-kernel@vger.kernel.org To: Peter Zijlstra Return-path: 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 In-Reply-To: <1242808954.26820.556.camel@twins> Sender: kvm-owner@vger.kernel.org List-ID: 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