Re: Limiting per vCPU Usage

[Peter Lieven]

Am 21.09.20 um 10:29 schrieb Daniel P. Berrangé:
> On Sun, Sep 20, 2020 at 10:24:41PM +0200, Peter Lieven wrote:
> > Hi Qemu folks,
> >
> >
> > is there a BCP to limit just the maximum usage of a virtual (KVM) cpu?
> >
> > I know that there are many approaches, but as far as I know they all limit the 
> > complete qemu process which is far more
> >
> > than just the virtual CPUs.
> >
> > Is it possible to limit just the vCPU threads and leave threads that
> > handle the monitor, vnc, qmp, iothreads, storage backend etc.
> Libvirt uses cgroups to achieve what you describe. A cgroup for the
> QEMU process as a whole, then create child cgroups, one for each
> vCPUs, and a further one for non-vCPU threads. CPU limits are then
> applied on the child cgroups.


Hi Daniel,


I came up with the same solution. Is there a nice way to get the thread ids of 
the vCPUs?

Iterating over all thread IDs and check the names works, but the thread names 
are not considered

a stable API (text from original commit message).


Thanks,

Peter