Messages in this thread | | | Subject | Re: hackbench regression due to commit 9dfc6e68bfe6e | From | "Zhang, Yanmin" <> | Date | Wed, 07 Apr 2010 10:20:40 +0800 |
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On Tue, 2010-04-06 at 15:55 -0500, Christoph Lameter wrote: > We cannot reproduce the issue here. Our tests here (dual quad dell) show a > performance increase in hackbench instead. I run hackbench on many machines. The regression exists on Nehalem machine (dual sockets, 2*4*2 logical cpu) and a tigerton (4 socket, 4*4 logical cpu) machines. I tried it on a dual quad core2 machine and it does like what you said.
The regression also exists on 2 new-generation Nehalem (dual socket 2*6*2 logical cpu) machines.
It seems hyperthreading cpu has more chances to trigger it.
> > Linux 2.6.33.2 #2 SMP Mon Apr 5 11:30:56 CDT 2010 x86_64 GNU/Linux > ./hackbench 100 process 200000 > Running with 100*40 (== 4000) tasks. > Time: 3102.142 > ./hackbench 100 process 20000 > Running with 100*40 (== 4000) tasks. > Time: 308.731 > ./hackbench 100 process 20000 > Running with 100*40 (== 4000) tasks. > Time: 311.591 > ./hackbench 100 process 20000 > Running with 100*40 (== 4000) tasks. > Time: 310.200 > ./hackbench 10 process 20000 > Running with 10*40 (== 400) tasks. > Time: 38.048 > ./hackbench 10 process 20000 > Running with 10*40 (== 400) tasks. > Time: 44.711 > ./hackbench 10 process 20000 > Running with 10*40 (== 400) tasks. > Time: 39.407 > ./hackbench 1 process 20000 > Running with 1*40 (== 40) tasks. > Time: 9.411 > ./hackbench 1 process 20000 > Running with 1*40 (== 40) tasks. > Time: 8.765 > ./hackbench 1 process 20000 > Running with 1*40 (== 40) tasks. > Time: 8.822 > > Linux 2.6.34-rc3 #1 SMP Tue Apr 6 13:30:34 CDT 2010 x86_64 GNU/Linux > ./hackbench 100 process 200000 > Running with 100*40 (== 4000) tasks. > Time: 3003.578 > ./hackbench 100 process 20000 > Running with 100*40 (== 4000) tasks. > Time: 300.289 > ./hackbench 100 process 20000 > Running with 100*40 (== 4000) tasks. > Time: 301.462 > ./hackbench 100 process 20000 > Running with 100*40 (== 4000) tasks. > Time: 301.173 > ./hackbench 10 process 20000 > Running with 10*40 (== 400) tasks. > Time: 41.191 > ./hackbench 10 process 20000 > Running with 10*40 (== 400) tasks. > Time: 41.964 > ./hackbench 10 process 20000 > Running with 10*40 (== 400) tasks. > Time: 41.470 > ./hackbench 1 process 20000 > Running with 1*40 (== 40) tasks. > Time: 8.829 > ./hackbench 1 process 20000 > Running with 1*40 (== 40) tasks. > Time: 9.166 > ./hackbench 1 process 20000 > Running with 1*40 (== 40) tasks. > Time: 8.681 > >
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