[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: Limiting per vCPU Usage
From: |
Daniel P . Berrangé |
Subject: |
Re: Limiting per vCPU Usage |
Date: |
Mon, 21 Sep 2020 15:09:45 +0100 |
User-agent: |
Mutt/1.14.6 (2020-07-11) |
On Mon, Sep 21, 2020 at 03:47:56PM +0200, Peter Lieven wrote:
> 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).
The QMP query-cpus command tells you thread IDs. There is similar for
I/O threads too. This is what libvirt uses to determine the mappings.
Regards,
Daniel
--
|: https://berrange.com -o- https://www.flickr.com/photos/dberrange :|
|: https://libvirt.org -o- https://fstop138.berrange.com :|
|: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|