Re: [Xen-devel] [PATCH 1 of 2 RFC] xen, pod: Zero-check recently populated pages (checklast)

[Tim Deegan <tim@xxxxxxx>]

At 15:24 +0100 on 14 Jun (1339687486), George Dunlap wrote:
> >>Also, wouldn't it be better to allocate this table dynamically, at
> >>once allowing its size to scale with the number of vCPU-s in the
> >>guest?
> >You could even make it a small per-vcpu array, assuming that the parallel
> >scrubbing will be symmetric across vcpus.
> I can't remember exactly what I found here (this was last summer I was 
> doing the tests); it may be that Windows creates a bunch of tasks which 
> may migrate to various cpus.  If that were the case, a global list would 
> be better than per-vcpu lists.
> 
> The problem with dynamically scaling the list is that I don't have a 
> heuristic to hand for how to scale it.
> 
> In both cases, it's not unlikely that making a change without testing 
> will significantly reduce the effectiveness of the patch.  Would you 
> rather hold off and wait until I can get a chance to run my benchmarks 
> again (which may miss the 4.2 cycle), or accept a tidied-up version of 
> this patch first, and hope to get a revised method (using dynamic 
> scaling or per-vcpu arrays) in before 4.2, but for sure by 4.3?

I'd be happy with the fixed size for 4.2.

Tim.

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