From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [PATCH 0/6] Kill off the virtio_net tx mitigation timer Date: Sun, 02 Nov 2008 11:48:04 +0200 Message-ID: <490D7754.4070807@redhat.com> References: <> <1225389113-28332-1-git-send-email-markmc@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: Avi Kivity , kvm@vger.kernel.org To: Mark McLoughlin Return-path: Received: from mx2.redhat.com ([66.187.237.31]:50215 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752937AbYKBJsI (ORCPT ); Sun, 2 Nov 2008 04:48:08 -0500 In-Reply-To: <1225389113-28332-1-git-send-email-markmc@redhat.com> Sender: kvm-owner@vger.kernel.org List-ID: Mark McLoughlin wrote: > Hey, > > The main patch in this series is 5/6 - it just kills off the > virtio_net tx mitigation timer and does all the tx I/O in the > I/O thread. > > What will it do to small packet, multi-flow loads (simulated by ping -f -l 30 $external)? Where does the benefit come from? Is the overhead of managing the timer too high, or does it fire too late and so we sleep? If the latter, can we tune it dynamically? For example, if the guest sees it is making a lot of progress without the host catching up (waiting on the tx timer), it can kick_I_really_mean_this_now(), to get the host to notice. -- error compiling committee.c: too many arguments to function