Re: [PATCH 0/5] kvm: Batch writes to MMIO

Avi Kivity
2008-05-26T13:43:29Z

Laurent Vivier wrote:
> Le lundi 26 mai 2008 à 15:00 +0300, Avi Kivity a écrit :
>
>> Laurent Vivier wrote:
>>
>>> When kernel has to send MMIO writes to userspace, it stores them
>>> in memory until it has to pass the hand to userspace for another
>>> reason. This avoids to have too many context switches on operations
>>> that can wait.
>>>
>>>
>>>
>> Looks good. The only issue I see is inconsistent naming. Sometimes you
>> use delayed_mmio, sometimes batched_mmio, and there's a way-too-generic
>> kvm_batch. Please stick to a single name throughout the code.
>>
>
> Which is your favorite ?
>
>

kvm_coalesced_mmio? :)

>>> VGA text scroll
>>> host_state_reload 13280568 (6:15) 3608362 (4:42) -73% (-25%)
>>>
>> This is probably better addressed by allowing the guest to write
>> directly to VRAM, like in the graphic modes.
>>
>
> Should I modify something in the patch ?
>

No, but when we direct-map text-mode vga, this benchmark will be obsolete.

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