A good news - sorry I wasn't aware of the current stance on arbitrary
parameters and can say I completely agree with it.
Scheduler Parameters API sounds interesting - i'll see if I can find
time to look into it - if there's anyone who already knows how it works
that sees this as a quick patch though, massive points
Henri
Daniel P. Berrange wrote:
On Tue, Sep 09, 2008 at 10:23:59PM +0100, Henri Cook wrote:
> Hey all,
>
> I'd quite like the ability to nice my KVM process, on a home basis this
> stops my Windows VM locking up my linux desktop when it's under load (or
> at least limits it) and in a commercial setting it might be nice to
> offer CPU priority to other customers or company backup-services over
> customer VPS instances for example.
>
> How does it sound? Any thoughts?
>
> A quick chat in #virt revealed that a method for adding generic KVM
> options has been under discussion for ages - I thought i'd throw my two
> cents in, what about some sort of expression with variables like:
>
A method for adding arbitrary KVM options will never be merged in
libvirt....
> <cmdstring>{cmd} {options}</cmdstring> (default)
>
> for my nice proposition you could:
>
> <cmdstring>/usr/bin/nice {cmd} {options}</cmdstring>
>
The intent of libvirt is to provide APIs which can be used across all
hypervisors. Taking the 'nice' example, this is really a schedular
parameter. If we added ability to set 'nice -20' in the XML for KVM,
there is no way we could possibly implement this for Xen.
So the goal is to find a consistent API representation. Fortunately we
do already have a 'schedular parameters' API in libvirt - we simply
need to decide how to implement this for KVM - a 'nice' setting is
certainly one schedular tunable we'd likely want to support.
So if someone wants to implenment the schedular parameters driver API
for KVM patches welcomed...
Regards,
Daniel