From owner-freebsd-emulation@FreeBSD.ORG Sun Dec 7 18:21:50 2008 Return-Path: Delivered-To: freebsd-emulation@FreeBSD.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id B5C7D1065670 for ; Sun, 7 Dec 2008 18:21:50 +0000 (UTC) (envelope-from nox@saturn.kn-bremen.de) Received: from gwyn.kn-bremen.de (gwyn.kn-bremen.de [212.63.36.242]) by mx1.freebsd.org (Postfix) with ESMTP id 325F18FC0C for ; Sun, 7 Dec 2008 18:21:50 +0000 (UTC) (envelope-from nox@saturn.kn-bremen.de) Received: by gwyn.kn-bremen.de (Postfix, from userid 10) id 18EE5191A2A; Sun, 7 Dec 2008 19:21:48 +0100 (CET) Received: from saturn.kn-bremen.de (noident@localhost [127.0.0.1]) by saturn.kn-bremen.de (8.14.2/8.13.8) with ESMTP id mB7IJRe7062179; Sun, 7 Dec 2008 19:19:27 +0100 (CET) (envelope-from nox@saturn.kn-bremen.de) Received: (from nox@localhost) by saturn.kn-bremen.de (8.14.2/8.13.6/Submit) id mB7IJQOT062178; Sun, 7 Dec 2008 19:19:26 +0100 (CET) (envelope-from nox) Date: Sun, 7 Dec 2008 19:19:26 +0100 (CET) From: Juergen Lock Message-Id: <200812071819.mB7IJQOT062178@saturn.kn-bremen.de> To: anthony@codemonkey.ws X-Newsgroups: local.list.qemu In-Reply-To: <493B35AB.1050301@codemonkey.ws> References: <20081206220906.GA34210@saturn.kn-bremen.de> Organization: home Cc: freebsd-emulation@FreeBSD.org, qemu-devel@nongnu.org Subject: Re: [Qemu-devel] testing qemu svn r5890 on FreeBSD - virtio, and a patch enabling -clock dynticks X-BeenThere: freebsd-emulation@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Development of Emulators of other operating systems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 07 Dec 2008 18:21:50 -0000 In article <493B35AB.1050301@codemonkey.ws> you write: >Juergen Lock wrote: >> Hi! >> >> Jung-uk Kim sent me a patch to enable -clock dynticks on FreeBSD hosts >> (the configure check is mine, only FreeBSD >= 7.x has posix timers that >> this uses), I'll append it below. >> >> This is the experimental qemu-devel port update I used: >> http://people.freebsd.org/~nox/qemu/qemu-devel-20081206.patch >> As already mentioned I had to add a missing `#include ' >> (files/patch-qemu-common.h), as also posted here: >> http://lists.gnu.org/archive/html/qemu-devel/2008-12/msg00216.html >> >> I only had one (type of) guest that actually had virtio drivers (three >> versions of sidux isos), and the speed difference between virtio-blk and >> scsi was small. (I tested dd bs=64k count=500 /dev/null and >> similar with a raw image, both scsi and virtio were always faster than ide.) >> I noted tho that even virtio there was not half as fast as ide (and scsi) >> on KNOPPIX_V5.3.1DVD-2008-03-26-EN.iso, so either overhead has increased >> greatly from 2.6.24.4 to 2.6.26, or this has something to do with >> the sidux kernel using CONFIG_NO_HZ and the Knoppix one (apparently) not >> and qemu (possibly, I also suspected that with the usb slowness) not >> handling CONFIG_NO_HZ guests too well. scsi on a FreeBSD >> 7.1-BETA-i386-livefs.iso guest btw was even yet (noticeably) faster than >> on the Knoppix iso. It will be interesting how virtio-net will fare once >> that gets committed... >> > >I don't have much experience with perf benchmarking and TCG. TCG may >has interesting side effects. For instance, it's more expensive to do >things in the guest instead of the host so the emulation overhead of >IDE/SCSI shouldn't matter much. > Actually most of those tests were with -kernel-kqemu sice that is what I usually run linux guests with. >A straight dd test is not the best test BTW. If you want to measure >performance, you should use O_DIRECT in the guest (iflag=direct) Hmm, how many guest processes will use that? Or is that what fses end up doing when the guest does things like, say, cp'ing files around? > and >probably O_DIRECT in the host (cache=none). Ok, will do next time... Thanx, Juergen