Re: [patch 04/17] Add pagetable accessors to pack and unpack pagetableentries

[Jeremy Fitzhardinge]

Ingo Molnar wrote:
> sure. i simply took the middle numbers. But there's definitely a 'few 
> percents' trend in the numbers.
>   

Yep. I guess the thing that coloured my summary is that I found overhead
of unpatched paravirt_ops calls surprisingly small.  I was really
expecting more like ~10% hit, but only null syscall approached that.

>>> this is not 'barely measurable' but 'BLOODY LARGE' overhead.
>>>       
>> Yes.  Fortunately there's a noticable difference between native and 
>> unpatched paravirt, because it shows all the effort we put into 
>> patching is worthwhile.
>>     
>
> if only it were not such an ugly piece of code? ;)
>   

Sigh, yes.  I've cleaned it up a bit since the last post, and commented
it, but I couldn't do much with its essential ugliness.  But I guess it
just got promoted from "ugly" to "ugly but necessary".

    J
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