Re: [RFC PATCH 0/3] generic hypercall support

From: Gregory Haskins
Date: Thu May 07 2009 - 13:04:16 EST


Chris Wright wrote:
> * Gregory Haskins (ghaskins@xxxxxxxxxx) wrote:
>
>> Chris Wright wrote:
>>
>>> VF drivers can also have this issue (and typically use mmio).
>>> I at least have a better idea what your proposal is, thanks for
>>> explanation. Are you able to demonstrate concrete benefit with it yet
>>> (improved latency numbers for example)?
>>>
>> I had a test-harness/numbers for this kind of thing, but its a bit
>> crufty since its from ~1.5 years ago. I will dig it up, update it, and
>> generate/post new numbers.
>>
>
> That would be useful, because I keep coming back to pio and shared
> page(s) when think of why not to do this. Seems I'm not alone in that.
>
> thanks,
> -chris
>

I completed the resurrection of the test and wrote up a little wiki on
the subject, which you can find here:

http://developer.novell.com/wiki/index.php/WhyHypercalls

Hopefully this answers Chris' "show me the numbers" and Anthony's "Why
reinvent the wheel?" questions.

I will include this information when I publish the updated v2 series
with the s/hypercall/dynhc changes.

Let me know if you have any questions.

-Greg

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