yade-dev team mailing list archive

[Klaus Thoeni <klaus.thoeni@xxxxxxxxx>]

Hi Bruno,

> 2/ Hyperthreading is completely useless for heavy computing tasks,
> actually even bad, as your results suggest.

I did some tests by enabling and disabling hyperthreading some time ago. 
Conclusions: always disable hyperthreading, as you say it makes no sense for 
the kind of thinks we are doing. Maybe we should mention it somewhere on our 
web page. Any suggestions where?

> Benchmarking 8 threads via this technique is irrelevant for this reason.
> What I would really like to see is how the collider scales with 8
> non-virtual cores and more.
> I think they can do that in Freiberg and Newcastle (in Grenoble as well,
> in fact, I just didn't find the time).

I did some testing with --performance on our grid on 3 different nodes and with 
various numbers of cores. I am rerunning the test with 500000 particles at the 
moment and will try to post a summary of all the results here or on the wiki 
later.

In the mean time some results of our slow AMD Opteron Processor 6282 SE:

****
yade -j4
5037  spheres, velocity= 94.8073682494 +- 3.55139591623 %
25103  spheres, velocity= 27.7389795715 +- 8.63375047506 %
50250  spheres, velocity= 16.0519684282 +- 5.60688183622 %
100467  spheres, velocity= 6.67235752786 +- 8.84758076674 %
200813  spheres, velocity= 2.66158958354 +- 7.70653861779 %

yade-pc -j4
5037  spheres, velocity= 78.264605326 +- 4.06741633055 %
25103  spheres, velocity= 26.0879865929 +- 2.61754448363 %
50250  spheres, velocity= 15.7245773611 +- 2.24679654566 %
100467  spheres, velocity= 7.64762330727 +- 2.59000324319 %
200813  spheres, velocity= 3.64194000319 +- 1.80798282427 %

********
yade -j8
5037  spheres, velocity= 138.024763661 +- 14.7299332104 %
25103  spheres, velocity= 35.7526851013 +- 4.24184671794 %
50250  spheres, velocity= 22.0071042904 +- 8.36195041437 %
100467  spheres, velocity= 11.1704832541 +- 11.725537817 %
200813  spheres, velocity= 3.54394003786 +- 5.48119712335 %

yade-pc -j8
5037  spheres, velocity= 133.311680084 +- 1.88168292497 %
25103  spheres, velocity= 34.3688804144 +- 7.43189318211 %
50250  spheres, velocity= 21.3620031259 +- 3.8532356508 %
100467  spheres, velocity= 11.3218727607 +- 3.77428592406 %
200813  spheres, velocity= 6.16209240352 +- 6.24680400297 %

********************************
yade -j16
5037  spheres, velocity= 71.8232644642 +- 41.7059425388 %
25103  spheres, velocity= 24.6342039841 +- 3.98148164778 %
50250  spheres, velocity= 16.1247061321 +- 4.73981941981 %
100467  spheres, velocity= 9.23509237236 +- 2.14822969955 %
200813  spheres, velocity= 2.91721702399 +- 3.88145803663 %

yade-pc -j16
5037  spheres, velocity= 129.908588625 +- 15.6874714595 %
25103  spheres, velocity= 33.526601121 +- 13.7594343427 %
50250  spheres, velocity= 17.7898704143 +- 7.7469432427 %
100467  spheres, velocity= 11.3877154372 +- 1.74832633634 %
200813  spheres, velocity= 6.95545612967 +- 2.35988760251 %

****************************************************************
yade -j32
5037  spheres, velocity= 59.0283160736 +- 51.2569740982 %
25103  spheres, velocity= 18.7622567759 +- 6.54660223453 %
50250  spheres, velocity= 12.3588048445 +- 8.49295845839 %
100467  spheres, velocity= 7.6569548227 +- 6.71719242602 %
200813  spheres, velocity= 2.47982732752 +- 10.4129796959 %

yade-pc -j32
5037  spheres, velocity= 88.9908888043 +- 15.7295668423 %
25103  spheres, velocity= 18.1857423869 +- 1.17387945175 %
50250  spheres, velocity= 12.6321967406 +- 5.31792620843 %
100467  spheres, velocity= 8.98513348696 +- 4.48699885744 %
200813  spheres, velocity= 6.12495571697 +- 1.48933071382 %

Summary for 200000 particles:
-> -j4: scale =1.37
-> -j8: scale =1.74
-> -j16: scale =2.38
-> -j32: scale =2.47

These numbers might look differently on our Intel nodes, I still have to check.

> What I need also before pushing to trunk is more testing with real
> scripts, not just --performance.
> I only covered a narrow range of situations with my own scripts, I would
> like to be sure that it will not break in other cases.

Maybe ask mister Fu, he really seems to be keen on increasing his computing 
scale ;-) 

Cheers
Klaus