Re: [Xen-devel] Diagnose stuff

[Juergen Gross <juergen.gross@xxxxxxxxxxxxxxxxxxx>]

Keir Fraser wrote:
> On 25/03/2009 08:24, "Juergen Gross" <juergen.gross@xxxxxxxxxxxxxxxxxxx>
> wrote:
> 
>> while implementing cpupool support in XEN I had to track down some issues
>> with deadlocks. Is there any interest in patches for the following?
>>
>> - compile time switchable spinlock timeout detection
> 
> NMI watchdog support effectively gets us this, and more general deadlock
> detection. Just put 'watchdog' on Xen's command line.

Sigh. I should have read ALL the code ;-)

> 
>> - printout of state of ALL cpus to console in case of hypervisor crash
> 
> Not sure how useful this would be really for most crashes. Probably we don't
> want it.

Okay. I'll let it rot here. :-)

> 
>> - some enhancements in lock handling to reduce (potential) latency:
>>   Today in *lock_irq and *lock_irqsave interrupts are disabled and then
>>   spinning is started. If the lock is not obtained, enabling and disabling of
>>   IRQs in the spinloop would block IRQs as short as possible.
> 
> Could do. I don't think our IRQ locks are very contended, but equally I
> suppose the patch is only a few lines.

I'll prepare a patch and let you decide.


Juergen

-- 
Juergen Gross                             Principal Developer
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