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Re: [Xen-devel] [PATCH, v2] reduce 'd' debug key's global impact

To: Jan Beulich <JBeulich@xxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH, v2] reduce 'd' debug key's global impact
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Thu, 6 May 2010 10:05:48 +0100
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On 06/05/2010 09:14, "Jan Beulich" <JBeulich@xxxxxxxxxx> wrote:

>>>> Keir Fraser <keir.fraser@xxxxxxxxxxxxx> 06.05.10 10:01 >>>
>> Although I suppose the event-check vector has a cleaner interface for
>> calling it and should be implemented for all architectures. If you add
>> whatever new flag you need to irq_cpustat_t then it would be cheap to check,
>> being a definite cache hit. I suppose each cpu would
>> check-and-check-and-clear it, and then set it for the next CPU when it is
>> done. That doesn't sound too bad.
> Hmm, isn't irq_cpustat_t being used mostly on the local CPU so far,
> and hence introducing reasons for bouncing the cache line wouldn't
> be nice?

It would only get bounced when the 'd' key is pressed, right? I think we
could tolerate that frequency of bounce. :-)

 -- Keir

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