[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] [PATCH] [HVM] Fix virtual apic irq distribution

On 28 Jun 2006, at 04:54, Dong, Eddie wrote:

In SMP guest, each VP has its TSC time and local APIC time which we need to sync them together like above UP approach. Ideally this per VP time should sync with platform time too like PIT (and thus all VP guest time is synced). But the problem is that some VPs may be deactive and thus no way to inject perioidic time IRQ no matter for LOCAL APIC time or PIT time. The solution will be very complicated to this and it may need to change scheduler to do switch in/out with affinity for VPs in same VM.

Yes, it sounds like PIT, LAPIC and TSC of all VCPUs will need to lag in sync with furthest-behind LAPIC or TSC of any VCPU. Yield-to in scheduler will be useful here.

Thanks for the detailed explanation.

 -- Keir

Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.