Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763318AbZDBP7M (ORCPT ); Thu, 2 Apr 2009 11:59:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1761036AbZDBP6v (ORCPT ); Thu, 2 Apr 2009 11:58:51 -0400 Received: from mx2.redhat.com ([66.187.237.31]:37596 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1763075AbZDBP6t (ORCPT ); Thu, 2 Apr 2009 11:58:49 -0400 Message-ID: <49D4E072.2060003@redhat.com> Date: Thu, 02 Apr 2009 18:57:38 +0300 From: Avi Kivity User-Agent: Thunderbird 2.0.0.21 (X11/20090320) MIME-Version: 1.0 To: Herbert Xu CC: Gregory Haskins , Rusty Russell , anthony@codemonkey.ws, andi@firstfloor.org, linux-kernel@vger.kernel.org, agraf@suse.de, pmullaney@novell.com, pmorreale@novell.com, netdev@vger.kernel.org, kvm@vger.kernel.org, Ingo Molnar Subject: Re: [RFC PATCH 00/17] virtual-bus References: <20090402085253.GA29932@gondor.apana.org.au> <49D487A6.407@redhat.com> <49D49C1F.6030306@novell.com> <200904022243.21088.rusty@rustcorp.com.au> <49D4B4A3.5070008@novell.com> <49D4B87D.2000202@redhat.com> <20090402145018.GA816@gondor.apana.org.au> <49D4D301.2090209@redhat.com> <20090402154041.GA1774@gondor.apana.org.au> In-Reply-To: <20090402154041.GA1774@gondor.apana.org.au> 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 Content-Length: 1412 Lines: 37 Herbert Xu wrote: > On Thu, Apr 02, 2009 at 06:00:17PM +0300, Avi Kivity wrote: > >> Good point - if we rely on having excess cores in the host, large guest >> scalability will drop. >> > > Going back to TX mitigation, I wonder if we could avoid it altogether > by having a "wakeup" mechanism that does not involve a vmexit. We > have two cases: > > 1) UP, or rather guest runs on the same core/hyperthread as the > backend. This is the easy one, the guest simply sets a marker > in shared memory and keeps going until its time is up. Then the > backend takes over, and uses a marker for notification too. > > The markers need to be interpreted by the scheduler so that it > knows the guest/backend is runnable, respectively. > Let's look at this first. What if the guest sends N packets, then does some expensive computation (say the guest scheduler switches from the benchmark process to evolution). So now we have the marker set at packet N, but the host will not see it until the guest timeslice is up? I think I totally misunderstood you. Can you repeat in smaller words? -- error compiling committee.c: too many arguments to function -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/