On 04/08/2011 06:25 PM, Luiz Capitulino wrote:
Hi there,
Summary:
- PXE boot in qemu.git (HEAD f124a41) is quite slow, more than 5 minutes. Got
the problem with e1000, virtio and rtl8139. However, pcnet *works* (it's
as fast as qemu-kvm.git)
- PXE boot in qemu-kvm.git (HEAD df85c051) is fast, less than a minute. Tried
with e1000, virtio and rtl8139 (I don't remember if I tried with pcnet)
I tried with qemu.git v0.13.0 in order to check if this was a regression, but
I got the same problem...
Then I inspected qemu-kvm.git under the assumption that it could have a fix
that wasn't commited to qemu.git. Found this:
- commit 0836b77f0f65d56d08bdeffbac25cd6d78267dc9 which is merge, works
- commit cc015e9a5dde2f03f123357fa060acbdfcd570a4 does not work (it's slow)
I tried a bisect, but it brakes due to gcc4 vs. gcc3 changes. Then I inspected
commits manually, and found out that commit 64d7e9a4 doesn't work, which makes
me think that the fix could be in the conflict resolution of 0836b77f, which
makes me remember that I'm late for diner, so my conclusions at this point are
not reliable :)
Can you run kvm_stat to see what the exit rates are?
Maybe we're missing a coalesced io in qemu.git? It's also possible that
gpxe is hitting the apic or pit quite a lot.
Regards,
Anthony Liguori
Ideas?
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