Date: Sat, 6 Dec 2008 23:31:40 +0100 From: Juergen Lock <nox@jelal.kn-bremen.de> To: qemu-devel@nongnu.org, freebsd-emulation@FreeBSD.org Subject: usb slowness again (was: testing qemu svn r5890 on FreeBSD - virtio, and a patch enabling -clock dynticks) Message-ID: <20081206223140.GA37972@saturn.kn-bremen.de> In-Reply-To: <20081206220906.GA34210@saturn.kn-bremen.de> References: <20081206220906.GA34210@saturn.kn-bremen.de>
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On Sat, Dec 06, 2008 at 11:09:06PM +0100, 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 <sys/uio.h>' > (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/vda >/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. [...] Well I just tried -usb -usbdevice net:vlan=1 -net user,vlan=1 with the Knoppix iso and got the same thruput (< 40 K/s) for wget on a local file than I got with sidux. So its probably not CONFIG_NO_HZ, at least not the usb slowness. Just thought I'd mention... Juergen
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