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 :|
