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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