Re: [Xen-devel] [PATCH] x86 hvm: freeze PIT/LAPIC timer emulation while its IRQ is masked

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

Perhaps. Anyway, the patches fixed bugs and generally cleaned up some logic,
so I think they are good for reasons other than the few saved cycles on
vmenter.

 -- Keir

On 16/09/2009 09:40, "Cui, Dexuan" <dexuan.cui@xxxxxxxxx> wrote:

> I'm not sure if the number of the saved cycles is the same on recent Intel
> CPUs, so the proportion may not be greater.  :-)
> 
> Thanks,
> -- Dexuan
> 
> -----Original Message-----
> From: Keir Fraser [mailto:keir.fraser@xxxxxxxxxxxxx]
> Sent: 2009?9?16? 16:21
> To: Cui, Dexuan; Kouya Shimura
> Cc: xen-devel@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [Xen-devel] [PATCH] x86 hvm: freeze PIT/LAPIC timer emulation
> while its IRQ is masked
> 
> On 16/09/2009 09:00, "Cui, Dexuan" <dexuan.cui@xxxxxxxxx> wrote:
> 
>> Looks the little win doesn't deserve the increased complexity in code.
>> 
>> BTW, recent Intel CPUs run much faster with respect to VMEntry/VMExit and
>> VMREAD/VMWRITE, so I don't think the SW optimizatin is appearling here. :-)
> 
> Makes it more appealing doesn't it? As this path will be a greater
> proportion of an overall vmexit/vmenter cycle.
> 
>  -- Keir



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