Re: [Xen-devel] Patch: implementing least priority interrupt routing

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

On 18/11/08 09:59, "Juergen Gross" <juergen.gross@xxxxxxxxxxxxxxxxxxx>
wrote:

> the attached patch implements interrupt routing to least priority processor
> for HVM domains.
> Instead of round robin the vcpu with the lowest processor priority is selected
> for the interrupt. If multiple vcpus share the same low priority interrupts
> are distributed between those round robin.
> Tested with BS2000 domain (3 vcpus, idle processors are now preferred
> interrupt target).

Where idle means 'not processing an interrupt'. Which ought to be by far the
most common case even for a non-idle CPU. Does this really improve load
balancing all that much? Does BS2000 spend lots of time in IRQ context?

My fear is that extra complexity here slows down dest_lowprio for all OSes
(and it's used by a lot of OSes) for every ExtInt delivered.

 -- Keir



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel