From mboxrd@z Thu Jan 1 00:00:00 1970 From: Avi Kivity Subject: Re: [patch 00/12] fake ACPI C2 emulation v2 Date: Wed, 04 Jun 2008 13:49:41 +0300 Message-ID: <48467345.90703@qumranet.com> References: <20080529222249.563011248@localhost.localdomain> <48426A19.4010000@qumranet.com> <20080602160859.GA3502@dmt.cnet> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Cc: Chris Wright , Glauber Costa , Anthony Liguori , kvm@vger.kernel.org To: Marcelo Tosatti Return-path: Received: from bzq-179-150-194.static.bezeqint.net ([212.179.150.194]:37274 "EHLO il.qumranet.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753970AbYFDKvq (ORCPT ); Wed, 4 Jun 2008 06:51:46 -0400 In-Reply-To: <20080602160859.GA3502@dmt.cnet> Sender: kvm-owner@vger.kernel.org List-ID: Marcelo Tosatti wrote: > On Sun, Jun 01, 2008 at 12:21:29PM +0300, Avi Kivity wrote: > >> Marcelo Tosatti wrote: >> >>> Addressing comments on the previous patchset, follows: >>> >>> - Same fake C2 emulation >>> - /dev/pmtimer >>> - Support for multiple IO bitmap pages + userspace interface >>> - In-kernel ACPI pmtimer emulation >>> >>> Tested with Linux and WinXP guests. Also tested migration. >>> >>> >> Do you have any performance numbers, comparing qemu/kernel/passthrough? >> > > Test is 1 million gettimeofday calls, Xeon 1.60GHz with 4MB L2. > > guest (qemu emulation): > cycles:1189759332 > > guest (in-kernel emulation): > cycles:628046412 > > guest (direct pmtimer): > cycles:230372934 > > host (TSC): > cycles:14862774 > > Ratio is 1:15:80 Looks like direct pmtimer is still quite slow. Are there any exits with direct pmtimer, or is it all due to the ioport latency? -- I have a truly marvellous patch that fixes the bug which this signature is too narrow to contain.