From mboxrd@z Thu Jan 1 00:00:00 1970 From: Marcelo Tosatti Subject: Re: [patch 0/4] use smp_send_reschedule in vcpu_kick / assigned dev host intx race fix Date: Wed, 29 Apr 2009 14:47:57 -0300 Message-ID: <20090429174757.GA7379@amt.cnet> References: <20090427210740.675732111@amt.cnet> <200904281508.47370.sheng@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: kvm@vger.kernel.org To: Sheng Yang Return-path: Received: from mx2.redhat.com ([66.187.237.31]:34142 "EHLO mx2.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1759896AbZD2SLV (ORCPT ); Wed, 29 Apr 2009 14:11:21 -0400 Content-Disposition: inline In-Reply-To: <200904281508.47370.sheng@linux.intel.com> Sender: kvm-owner@vger.kernel.org List-ID: On Tue, Apr 28, 2009 at 03:08:46PM +0800, Sheng Yang wrote: > Ack all. This also solved one bug by my hand. Thanks! > > I observe one point: the performance of high workload interrupt(e.g. 10 > gigabyte oplin card) dropped dramatically with smp_send_reschedule() method... > In one environment(the speed of oplin card also limited by cpu performance), > Using smp_call_function_single() can get more than 1G bit/s stably(native got > 1.2G), but smp_send_reschedule() can only got around 600M bit/s... And the > rescheduling interrupt number is about 2000/second per cpu. And the interrupt > rate is about tens of thousands per second for the device. > > Anyway, this method is more elegant and correct. Though there is still room > for optimize - but of course, the correctness is first priority. Are you using the compat code or a kvm.git kernel? Can you remove only the last patch (the spinlock) to confirm its the cause of the slowdown?