From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Michael S. Tsirkin" Subject: Re: TODO list for qemu+KVM networking performance v2 Date: Wed, 10 Jun 2009 19:28:41 +0300 Message-ID: <20090610162841.GK28601@redhat.com> References: <20090604164320.GB14592@redhat.com> <200906101309.14532.rusty@rustcorp.com.au> <4A2F5217.9090401@redhat.com> <200906110009.34671.rusty@rustcorp.com.au> <20090610145358.GB28601@redhat.com> <4A2FCEA9.8010604@redhat.com> <20090610155428.GI28601@redhat.com> <4A2FDA91.4070903@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: Rusty Russell , dlaor@redhat.com, virtualization@lists.linux-foundation.org, Chris Wright , Mark McLoughlin , kvm@vger.kernel.org, Brian Stein , Herbert Xu , Dor Laor , Yaron Haviv , Shahar Klein , Anthony Liguori To: Avi Kivity Return-path: Received: from mx2.redhat.com ([66.187.237.31]:42010 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753220AbZFJQaM (ORCPT ); Wed, 10 Jun 2009 12:30:12 -0400 Content-Disposition: inline In-Reply-To: <4A2FDA91.4070903@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: On Wed, Jun 10, 2009 at 07:08:49PM +0300, Avi Kivity wrote: > Michael S. Tsirkin wrote: >> On Wed, Jun 10, 2009 at 06:18:01PM +0300, Avi Kivity wrote: >> >>> Michael S. Tsirkin wrote: >>> >>>> But I don't understand how aio will make implementing it easier - >>>> or are you merely saying that it will make it worthwhile? >>>> >>> If you have aio, the the NIC and the guest proceed in parallel. If >>> the guest is faster (likely), then when it sends the next packet it >>> will see that interrupts are disabled and not notify again. Once >>> aio complete we can recheck the queue; if it's empty we reenable >>> notifications. If there's still stuff in it we submit it with >>> notifications disabled. >>> >> >> So you are saying that with aio we won't need this optimization at all? >> I guess it's late in the day, and my mind is fuzzy... >> > > No, I'm saying with aio the optimization becomes worthwhile. But I > joined late in the thread so we may be talking about different things. Oh, I see that. What Rusty's saying is that it's not as trivial as it seems, and I agree. And at some point it seemed like he was saying it's easier to implement with aio, but that probably was just my misunderstanding. -- MST