Re: kvm very slow

Ulrich Schreiner
2007-08-07T07:20:36Z

no ideas what can be done? why it is so slow?

i've tried the "-L /usr/shar/kvm" to use the kvm-bios but no better
performance ...

Am Donnerstag, den 02.08.2007, 11:24 +0300 schrieb Avi Kivity:
> Ulrich Schreiner wrote:
> > dmesg|grep kvm
> >
> > SELinux: initialized (dev kvmfs, type kvmfs), uses genfs_contexts
> > kvm: emulating exchange as write
> >
> >
>
> There may be messages that aren't prefixed with 'kvm:' (that's a bug
> btw). Please check.
>
> > now booting into a F7 image, after the system is ready (and in idle):
> >
> > top
> > PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
> > 14917 root 20 0 332m 71m 66m S 6 0.9 1:17.05 qemu-kvm
> > 14954 root 20 0 14552 1072 812 R 0 0.0 0:00.01 top
> > 1 root 20 0 10320 680 572 S 0 0.0 0:02.02 init
> >
> > kvm_stat (snapshot):
> >
> > kvm statistics
> >
> > exits 12254399 79079
> > halt_exits 326543 4632
> > invlpg 0 0
> > io_exits 6539798 74320
> > irq_exits 43523 29
> > irq_window 4984 0
> > mmio_exits 1319016 0
> > pf_fixed 3140955 56
> > pf_guest 448187 6
> > request_irq 0 0
> > signal_exit 39728 0
> > tlb_flush 29511 31
> >
>
> Wow -- lots of I/O exits. What does 'top' in the guest say? 'hdparm
> /dev/hda' in the guest?
>
> > when logging into the virtual machine (via ssh) the virtual world is
> > very slow: i set the time with "ntpdate" and wait exact one minute in
> > reality. in the virtual image only 24sec are gone!
> >
> > and everything else in the image is really slow.
> >
> >