Re: [Xen-devel] IRQ SMP affinity problems in domU with vcpus > 4 on HP ProLiant G6 with dual Xeon 5540 (Nehalem)

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

On 08/10/2009 19:11, "Cinco, Dante" <Dante.Cinco@xxxxxxx> wrote:

> The IRQ SMP affinity problem happens on just the passthrough one using MSI.
> 
> I've only used Xen 3.4.1. Are you aware of recent code changes that may
> address this issue?

No, but it might be worth a try. Unfortunately I'm not so familiar with the
MSI passthru code as I am with the rest of the irq emulation layer. Qing He
(cc'ed) may be able to assist, as I think he did much of the development of
MSI support for passthru devices.

 -- Keir

> Dante
> 
> -----Original Message-----
> From: Keir Fraser [mailto:keir.fraser@xxxxxxxxxxxxx]
> Sent: Thursday, October 08, 2009 11:06 AM
> To: Cinco, Dante; xen-devel@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [Xen-devel] IRQ SMP affinity problems in domU with vcpus > 4 on
> HP ProLiant G6 with dual Xeon 5540 (Nehalem)
> 
> On 08/10/2009 01:08, "Cinco, Dante" <Dante.Cinco@xxxxxxx> wrote:
> 
>> One of my questions is "Why does domU use only even numbered APIC
>> IDs?" If it used odd numbers, then physical flat APIC routing will
>> only trigger when vcpus
>>> 7.
> 
> It's just the mapping we use. Local APICs get even numbers, IOAPIC gets id 1.
> 
>> I welcome any suggestions on how to pursue this problem or hopefully,
>> someone will say that a patch for this already exists.
> 
> Is this true for all interrupts, or just the passthrough one using MSI?
> 
> What Xen version are you using? You say '3.4 unstable' - do you mean tip of
> xen-3.4-testing.hg? Have you tried xen-unstable.hg (current developemnt tree)?
> 
>  -- Keir
> 
> 



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