Re: doubled idle count

Ferenc Wagner
2008-09-19T13:20:50Z

Jeremy Fitzhardinge <jeremy@goop.org> writes:

> Ferenc Wagner wrote:
>
>> After upgrading a Xen virtual machine to Debian's 2.6.26-4 kernel, I
>> noticed that the idle counter doubled its pace on one of the machines:
>> [...]
>> One out of three machines show this effect, with the exact same kernel
>> and Xen versions (3.2.0, dom0 is Debian's stock Etch 2.6.18 kernel).
>> They aren't hosted by the same machine, though: the misbehaving one is
>> on a different installation with very similar hardware (3 vs 2 GHz).
>> All the guest are paravirtual.
>
> So you're saying that they are identical Xen and guest kernel binaries,
> but one of three is showing doubled idle time?

Now I upgraded another domU, and that also shows this doubling effect,
so I've got two domUs (running on xen2-ha) misbehaving, and other two
(running on xen2) behaving correctly. On the first:

wferi@xen2-ha:~$ sudo xm info
host : xen2-ha
release : 2.6.18-6-xen-686
version : #1 SMP Mon Aug 18 12:56:50 UTC 2008
machine : i686
nr_cpus : 4
nr_nodes : 1
cores_per_socket : 1
threads_per_core : 2
cpu_mhz : 3056
hw_caps : bfebfbff:00000000:00000000:00000080:00004400
total_memory : 3071
free_memory : 991
node_to_cpu : node0:0-3
xen_major : 3
xen_minor : 2
xen_extra : -1
xen_caps : xen-3.0-x86_32p
xen_scheduler : credit
xen_pagesize : 4096
platform_params : virt_start=0xf5800000
xen_changeset : unavailable
cc_compiler : gcc version 4.1.2 20061115 (prerelease) (Debian 4.1.1-21)
cc_compile_by : fs
cc_compile_domain : debian.org
cc_compile_date : Mon Mar 10 15:50:27 UTC 2008
xend_config_format : 4

while on the other the differing lines are:

host : xen2
cpu_mhz : 1993
total_memory : 4991
free_memory : 2464

Hope this adds some useful info.
--
Regards,
Feri.