[Xen-devel] Re: Xen 4.1 interrupts not delievered.

[Sander Eikelenboom <linux@xxxxxxxxxxxxxx>]

Hello Keir,

OK let's rephrase, in what cases is it logical that the xen serial console 
freezes together with dom0 ?
For example some deadlock causes cpu0 to stall on a heavily loaded system ..
I think having the serial console available to dump the machines state is quite 
vital :-(

I have tried the max_cstate=1 together with the latest 2.6.32-xen-next-pvops 
kernel as dom0 kernel (which Ian's fix to the event channels).
But with the compile test it freezes just as fast.
Will try xen before changesets 20072/20073 now, probably with 2.6.31 pvops, 
since 2.6.32 would need a more recent hypervisor.

--
Sander


Wednesday, October 13, 2010, 1:34:58 AM, you wrote:

> On 12/10/2010 18:17, "Konrad Rzeszutek Wilk" <konrad.wilk@xxxxxxxxxx> wrote:

>> A couple of that might fix the problems are:
>> 
>>  1). Ian's fix to the event channels:
>> http://xenbits.xen.org/gitweb?p=people/ianc/linux-2.6.git;a=commit;h=5d30cb2a8
>> 5912ffb5f6556d55472c26801eef2ea
>>  2). Disable IRQ balancing in Xen (and also in Linux kernel). "noirqbalance"
>>  3). Pin domains, but nothing to Domain 0.

> ITYM cpu 0. Not that this should rightly make any difference that I can see.

> My suspicion would be the per-CPU IDT patches introduced during 4.0
> development. Or changes to enable deep C-state sleeps by default. One or the
> other causing lost interrupts. I think the latter can be discounted by
> max_cstate=1 as a Xen boot parameter. The former would require trying a
> build of Xen before and after changesets 20072/20073 -- they are the ones
> that did the heavy lifting to implement per-CPU IDTs.

>  -- Keir

>> But it might be worth trying them out?





-- 
Best regards,
 Sander                            mailto:linux@xxxxxxxxxxxxxx


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