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

[Gregory Haskins <ghaskins@novell.com>]

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David S. Ahern wrote:
> Marcelo Tosatti wrote:
>   
>> On Fri, May 08, 2009 at 10:45:52AM -0400, Gregory Haskins wrote:
>>     
>>> Marcelo Tosatti wrote:
>>>       
>>>> On Fri, May 08, 2009 at 10:55:37AM +0300, Avi Kivity wrote:
>>>>   
>>>>         
>>>>> Marcelo Tosatti wrote:
>>>>>     
>>>>>           
>>>>>> Also it would be interesting to see the MMIO comparison with EPT/NPT,
>>>>>> it probably sucks much less than what you're seeing.
>>>>>>   
>>>>>>       
>>>>>>             
>>>>> Why would NPT improve mmio?  If anything, it would be worse, since the  
>>>>> processor has to do the nested walk.
>>>>>
>>>>> Of course, these are newer machines, so the absolute results as well as  
>>>>> the difference will be smaller.
>>>>>     
>>>>>           
>>>> Quad-Core AMD Opteron(tm) Processor 2358 SE 2.4GHz:
>>>>
>>>> NPT enabled:
>>>> test 0: 3088633284634 - 3059375712321 = 29257572313
>>>> test 1: 3121754636397 - 3088633419760 = 33121216637
>>>> test 2: 3204666462763 - 3121754668573 = 82911794190
>>>>
>>>> NPT disabled:
>>>> test 0: 3638061646250 - 3609416811687 = 28644834563
>>>> test 1: 3669413430258 - 3638061771291 = 31351658967
>>>> test 2: 3736287253287 - 3669413463506 = 66873789781
>>>>
>>>>   
>>>>         
>>> Thanks for running that.  Its interesting to see that NPT was in fact
>>> worse as Avi predicted.
>>>
>>> Would you mind if I graphed the result and added this data to my wiki? 
>>> If so, could you adjust the tsc result into IOPs using the proper
>>> time-base and the test_count you ran with?   I can show a graph with the
>>> data as is and the relative differences will properly surface..but it
>>> would be nice to have apples to apples in terms of IOPS units with my
>>> other run.
>>>
>>> -Greg
>>>       
>> Please, that'll be nice.
>>
>> Quad-Core AMD Opteron(tm) Processor 2358 SE
>>
>> host: 2.6.30-rc2
>> guest: 2.6.29.1-102.fc11.x86_64
>>
>> test_count=1000000, tsc freq=2402882804 Hz
>>
>> NPT disabled:
>>
>> test 0 = 2771200766
>> test 1 = 3018726738
>> test 2 = 6414705418
>> test 3 = 2890332864
>>
>> NPT enabled:
>>
>> test 0 = 2908604045
>> test 1 = 3174687394
>> test 2 = 7912464804
>> test 3 = 3046085805
>>
>>     
>
> DL380 G6, 1-E5540, 6 GB RAM, SMT enabled:
> host: 2.6.30-rc3
> guest: fedora 9, 2.6.27.21-78.2.41.fc9.x86_64
>
> with EPT
> test 0: 543617607291 - 518146439877 = 25471167414
> test 1: 572568176856 - 543617703004 = 28950473852
> test 2: 630182158139 - 572568269792 = 57613888347
>
>
> without EPT
> test 0: 1383532195307 - 1358052032086 = 25480163221
> test 1: 1411587055210 - 1383532318617 = 28054736593
> test 2: 1471446356172 - 1411587194600 = 59859161572
>
>
>   

Thank you kindly, David.

-Greg



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