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

[Avi Kivity <avi@redhat.com>]

On 10/20/2009 04:48 PM, Tomasz Chmielewski wrote:
> Avi Kivity wrote:
>> On 10/20/2009 10:19 PM, Tomasz Chmielewski wrote:
>>>>
>>>> I meant, how many qemu threads are there, and how much cpu does 
>>>> each take?
>>>
>>>
>>> There is only one qemu thread for the 4-cpu guest.
>>
>> Not possible.  Even a single-cpu guest has two threads.
>
> "ps auxH" shuld show me all threads? I started it multiple times, and 
> it shown 1 thread for the 4-CPU guest
> (with no CPU intensive tasks running - could this be a reason?).

No.  kvm implies 2+ threads.

>
>
>> What does 'ls /proc/$(pgrep qemu)/task' show?
>
> Running several CPU-intensive processes on this guest uses only one 
> CPU on the host.
>
> Both "ps auxH" and /proc confirm that this guest has 4-5 threads when 
> I run several CPU-intensive apps.
>
> Only one thread for this guest uses 100% CPU time; other threads use ~0%.
>
> If I don't run any CPU-intensive tasks on this guests, it only runs 
> one thread (unless I misinterpret something here).
>
>
> Some 1-CPU guests have only one thread though?
>

Are you sure they're using kvm?  Try 'info kvm' in the monitor.  tcg 
will only use on thread (more will be spawned for I/O, but will 
eventually die).

-- 
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