Re: 0.11: SMP guests using one host CPU only?

[Tomasz Chmielewski <mangoo@wpkg.org>]

Avi Kivity wrote:
> On 10/20/2009 06:03 PM, Tomasz Chmielewski wrote:
>> On a 8 CPU host, I created a guest with 4 CPUs (-smp 4).
>>
>> Unfortunately, the guest only uses one host CPU.
>> For example, running "cat /dev/urandom | gzip -9 >/dev/null &" several 
>> times on this guest causes load on only one host CPU.
>>
>> Is it expected?
> 
> No.  What does 'top -H' show?

In the guest - 4 CPUs with ~100% usage each (when I press "1"), otherwise, in the task list, multiple "cat" processes taking most CPU time (as it reads from /dev/urandom).


In the host - qemu-system-x86 (one process/thread) taking ~100% CPU; when I press "1", I see only one CPU is used 100%, 7 other CPUs are more or less not used.


guest command line:


/usr/bin/qemu-system-x86_64 -m 1024 -drive file=/srv/kvm/images/lvs2,if=virtio,cache=writeback,index=0,boot=on -net nic,vlan=0,model=virtio,macaddr=F2:4A:51:41:B1:3F -net tap,vlan=0,script=/etc/qemu-ifup -localtime -smp 4


There are 5 other guests (1 CPU) started before this guest.


-- 
Tomasz Chmielewski
http://wpkg.org