Re: kvm guest: hrtimer: interrupt too slow

[Avi Kivity <avi@redhat.com>]

On 09/29/2009 03:12 PM, Michael Tokarev wrote:
> Hello.
>
> I'm having quite an.. unusable system here.
> It's not really a regresssion with 0.11.0,
> it was something similar before, but with
> 0.11.0 and/or 2.6.31 it become much worse.
>
> The thing is that after some uptime, kvm
> guest prints something like this:
>
> hrtimer: interrupt too slow, forcing clock min delta to 461487495 ns
>
> after which system (guest) speeed becomes
> very slow.  The above message is from
> 2.6.31 guest running wiht 0.11.0 & 2.6.31
> host.  Before I tried it with 0.10.6 and
> 2.6.30 or 2.6.27, and the delta were a
> bit less than that:
>
> hrtimer: interrupt too slow, forcing clock min delta to 152222415 ns
> hrtimer: interrupt too slow, forcing clock min delta to 93629025 ns
>
> etc.
>
> Before, guest was just somewhat slow.  But
> now, it reached the state when it's almost
> unusable.
>
> Especially "nice" it's visible in xterm
> (running on that guest): typing a single
> char in xterm results in it being displayed
> after 1..2 sec pause.  With applications
> like web browser (where all the font
> rendering is done on the client and X
> server receives bitmap instead of a
> character code to draw, it isn't that
> bad.
>
> I suspect it's only happening with small
> network packets.
>
> The above message (with large min delta)
> occured after about 20 hours uptime.  Similar
> (give or take) delays were observed previously
> as well.  That to say, -- it's not something
> you notice immediately.
>
> The problem is quite consistent, that is,
> different guests shows it sooner or later.
>
> Right now I'm running 2.6.31-amd64 host,
> 32bit qemu-kvm-0.11.0, 2.6.31-i686 uniprocessor
> guest, virtio networking and block devices,
> kvm-clock is enabled.  Similar configuration
> were used before (with different versions).
> The hardware is Phenom 9750 (4core) running
> on Amd780g/sb700 chipset.
>
> Any hints on what to do with all this?
>

What happens if you use hpet or pmtimer as guest clocksource?

Please post host /proc/cpuinfo.

-- 
error compiling committee.c: too many arguments to function