Re: [Xen-devel] [Patch 2 of 2]: PV-domain SMP performance Linux-part

[Juergen Gross <juergen.gross@xxxxxxxxxxxxxxxxxxx>]

Keir Fraser wrote:
> On 19/12/2008 09:25, "Juergen Gross" <juergen.gross@xxxxxxxxxxxxxxxxxxx>
> wrote:
> 
>>> I haven't seen any win on any real world setup. So I remain unconvinced, and
>>> it'll need more than you alone championing the patch to get it in. There
>>> have been no other general comments so far (Jan's have been about specific
>>> details).
>> Okay, would the following scenario be "real world" enough?
>>
>> Multiple domUs being busy leading to enough vcpu scheduling, several parallel
>> kernel builds in dom0 acting as benchmark.
> 
> Something like that would be better. Of course you'd need to measure work
> done in the domUs as well, as one of the critical factors for this patch
> would be how it affects fairness. It's one reason I'm leery of this patch --
> our scheduler is unpredictable enough as it is without giving domains
> another lever to pull!

Keir, is the data I posted recently okay?
I think my approach requires less changes than the "yield after spin" variant,
which needed more patches in the hypervisor and didn't seem to be settled.
Having my patches in the hypervisor at least would make life much easier for
our BS2000 system...
I would add some code to ensure a domain isn't misusing the new interface.

Juergen

-- 
Juergen Gross                             Principal Developer
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