On 3/31/10, Anthony Liguori <anth...@codemonkey.ws> wrote: > On 03/31/2010 02:07 PM, Michael S. Tsirkin wrote: > > > On Wed, Mar 31, 2010 at 03:38:05PM -0300, Luiz Capitulino wrote: > > > > > > > On Wed, 31 Mar 2010 13:26:23 -0500 > > > Anthony Liguori<anth...@codemonkey.ws> wrote: > > > > > > > > > > > > > On 03/31/2010 01:20 PM, Michael S. Tsirkin wrote: > > > > > > > > > > > > > From: David L Stevens<dlstev...@us.ibm.com> > > > > > > > > > > vhost driver in qemu didn't ack features, and this happens > > > > > to work because we don't really require any features. However, > > > > > it's better not to rely on this. This patch passes features to > > > > > vhost as guest acks them. > > > > > > > > > > Signed-off-by: David L Stevens<dlstev...@us.ibm.com> > > > > > Signed-off-by: Michael S. Tsirkin<m...@redhat.com> > > > > > --- > > > > > > > > > > Anthony, here's a fixup patch to address an issue in vhost > > > > > patches. Incidentially, what's the status of the vhost patchset? > > > > > > > > > > > > > > > > > > > > http://repo.or.cz/w/qemu/aliguori-queue.git > vhost > > > > > > > > Is what I'm currently testing. With vhost disabled, the following > seg > > > > faults: > > > > > > > > qemu-system-x86_64 -hda ~/images/linux.img -net tap -net > > > > nic,model=virtio -enable-kvm > > > > > > > > But not when using TCG. I'm not sure that it's your patches at fault > > > > and I'm attempting to bisect now to figure that out. > > > > > > > > > > > Probably this is the same segfault I'm getting right > now in master, > > > bisect says it's: > > > > > > """ > > > commit ad96090a01d848df67d70c5259ed8aa321fa8716 > > > Author: Blue Swirl<blauwir...@gmail.com> > > > Date: Mon Mar 29 19:23:52 2010 +0000 > > > > > > Refactor target specific handling, compile vl.c only once > > > """ > > > > > > > > Why are the compile once patches helpful? They seem to > introduce > > churn and bugs, they actively make it harder to extend qemu as you can't > use > > target-specific code in code that is compiled once, they might have > > performance penalty - and what do we gain? Any given user is unlikely to > > need to build on more than one target, distros have enough computing > > power to build in parallel. > > > > Maybe it makes sense to revert the compile once patches, and discuss > > these issues before re-commit? > > > > > > Compiling objects once is certainly useful. Long term, I think most of us > want to see a single qemu executable that works for all architectures and > compiling once is an important step in that direction. > > With respect to regressions, it might make sense to slow down these > refactorings a bit and increase the amount of regression testing that is > happening during them.
I think there are only a few useful refactorings left. MIPS was interesting because of fourfold savings, likewise triple savings with PPC. Refactoring i386/x86_64 devices may be worthwhile, the rest not.
