From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sheng Yang Subject: Re: [patch 0/4] use smp_send_reschedule in vcpu_kick / assigned dev host intx race fix Date: Thu, 30 Apr 2009 08:56:57 +0800 Message-ID: <200904300856.57926.sheng@linux.intel.com> References: <20090427210740.675732111@amt.cnet> <200904281508.47370.sheng@linux.intel.com> <20090429174757.GA7379@amt.cnet> Mime-Version: 1.0 Content-Type: Text/Plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Cc: kvm@vger.kernel.org To: Marcelo Tosatti Return-path: Received: from mga05.intel.com ([192.55.52.89]:16787 "EHLO fmsmga101.fm.intel.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1753200AbZD3A47 (ORCPT ); Wed, 29 Apr 2009 20:56:59 -0400 In-Reply-To: <20090429174757.GA7379@amt.cnet> Content-Disposition: inline Sender: kvm-owner@vger.kernel.org List-ID: On Thursday 30 April 2009 01:47:57 Marcelo Tosatti wrote: > 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? I am using kvm.git. I said this because I tried the old version of patch(which have warning) and it would got more than 1G/sec. I'd like to take a close look at what's happened. -- regards Yang, Sheng