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Re: [Qemu-devel] Slow PXE boot in qemu.git (fast in qemu-kvm.git)
From: |
Luiz Capitulino |
Subject: |
Re: [Qemu-devel] Slow PXE boot in qemu.git (fast in qemu-kvm.git) |
Date: |
Mon, 11 Apr 2011 15:35:19 -0300 |
On Fri, 08 Apr 2011 19:50:57 -0500
Anthony Liguori <address@hidden> wrote:
> 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?
Here you go, both collected after the VM is fully booted:
qemu.git:
efer_reload 0 0
exits 159767195 99
fpu_reload 203 0
halt_exits 544 27
halt_wakeup 0 0
host_state_reload 299851 70
hypercalls 0 0
insn_emulation 134495973 41
insn_emulation_fail 0 0
invlpg 9687 0
io_exits 85979 0
irq_exits 162179 4
irq_injections 11582 27
irq_window 20712 27
largepages 0 0
mmio_exits 9545 41
mmu_cache_miss 5307 0
mmu_flooded 2493 0
mmu_pde_zapped 1188 0
mmu_pte_updated 5355 0
mmu_pte_write 181550 0
mmu_recycled 0 0
mmu_shadow_zapped 6437 0
mmu_unsync 15 0
nmi_injections 0 0
nmi_window 0 0
pf_fixed 73983 0
pf_guest 4027 0
remote_tlb_flush 1 0
request_irq 6 0
signal_exits 135731 2
tlb_flush 26760 0
qemu-kvm.git:
efer_reload 0 0
exits 8697244 33
fpu_reload 46 0
halt_exits 206 8
halt_wakeup 7 0
host_state_reload 105173 8
hypercalls 0 0
insn_emulation 6984118 21
insn_emulation_fail 0 0
invlpg 9682 0
io_exits 626201 0
irq_exits 22930 4
irq_injections 2815 8
irq_window 1029 0
largepages 0 0
mmio_exits 3657 0
mmu_cache_miss 5271 0
mmu_flooded 2466 0
mmu_pde_zapped 1146 0
mmu_pte_updated 5294 0
mmu_pte_write 191173 0
mmu_recycled 0 0
mmu_shadow_zapped 6405 0
mmu_unsync 17 0
nmi_injections 0 0
nmi_window 0 0
pf_fixed 73580 0
pf_guest 4169 0
remote_tlb_flush 1 0
request_irq 0 0
signal_exits 24873 0
tlb_flush 26628 0
>
> 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?
> > --
> > To unsubscribe from this list: send the line "unsubscribe kvm" in
> > the body of a message to address@hidden
> > More majordomo info at http://vger.kernel.org/majordomo-info.html
>
- [Qemu-devel] Slow PXE boot in qemu.git (fast in qemu-kvm.git), Luiz Capitulino, 2011/04/08
- [Qemu-devel] Re: Slow PXE boot in qemu.git (fast in qemu-kvm.git), Anthony Liguori, 2011/04/08
- [Qemu-devel] Re: Slow PXE boot in qemu.git (fast in qemu-kvm.git), Stefan Hajnoczi, 2011/04/09
- [Qemu-devel] Re: Slow PXE boot in qemu.git (fast in qemu-kvm.git), Avi Kivity, 2011/04/10
- Re: [Qemu-devel] Slow PXE boot in qemu.git (fast in qemu-kvm.git),
Luiz Capitulino <=
- Re: [Qemu-devel] Slow PXE boot in qemu.git (fast in qemu-kvm.git), Alex Williamson, 2011/04/11
- Re: [Qemu-devel] Slow PXE boot in qemu.git (fast in qemu-kvm.git), Luiz Capitulino, 2011/04/11
- Re: [Qemu-devel] Slow PXE boot in qemu.git (fast in qemu-kvm.git), Jan Kiszka, 2011/04/12
- Re: [Qemu-devel] Slow PXE boot in qemu.git (fast in qemu-kvm.git), Anthony Liguori, 2011/04/11
- Re: [Qemu-devel] Slow PXE boot in qemu.git (fast in qemu-kvm.git), Avi Kivity, 2011/04/12
- Re: [Qemu-devel] Slow PXE boot in qemu.git (fast in qemu-kvm.git), Luiz Capitulino, 2011/04/11
- Re: [Qemu-devel] Slow PXE boot in qemu.git (fast in qemu-kvm.git), Jan Kiszka, 2011/04/11
- Re: [Qemu-devel] Slow PXE boot in qemu.git (fast in qemu-kvm.git), Alex Williamson, 2011/04/11
- Re: [Qemu-devel] Slow PXE boot in qemu.git (fast in qemu-kvm.git), Jan Kiszka, 2011/04/11
- Re: [Qemu-devel] Slow PXE boot in qemu.git (fast in qemu-kvm.git), Jan Kiszka, 2011/04/11