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

["David S. Ahern" <daahern@cisco.com>]

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


david


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