Re: Dom0 losing interrupts???

[Juergen Gross <juergen.gross@ts.fujitsu.com>]

On 02/14/11 10:26, Jan Beulich wrote:
>>>> On 14.02.11 at 07:59, Juergen Gross<juergen.gross@ts.fujitsu.com>  wrote:
>> I used xen-unstable, kernel 2.6.32.24 from SLES11 SP1 on a 12 core INTEL
>> nehalem machine. I pinned all 12 Dom0 vcpus to pcpu 1-2 and started a
>> parallel
>> build. After about 2 minutes the first missing interrupts were reported, a
>> little bit later the next one, no xen messages are printed:
>
> That's certainly not too surprising, somewhat depending on the
> maximally tolerated latencies. It seems unlikely to me for a 6-fold
> CPU over-commit to promise stable operation, yet certain
> adjustments could probably be done to make it work better (like
> temporarily boosting the priority of a hardware interrupt's target
> vCPU).

I would understand timeouts. But shouldn't the interrupt come in sooner or
later? At least the megasas driver seems not to be able to recover from this
problem, as a result my root filesystem is set to read-only...

This would mean there is a problem in the megasas driver, correct?
And Andre reports stability problems of his machine in similar cases, but
in his case the network driver seems to be the reason.

Are you planning to prepare a patch for boosting the priority of vcpus being
the target for a hardware interrupt? I think I would have to search some time
to find the correct places to change...


Juergen

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Juergen Gross                 Principal Developer Operating Systems
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