[parsec-users] Fluid animate
mbb45 at cornell.edu
Thu Jun 10 13:21:57 EDT 2010
Thanks Jim, the note1-3 results look quite interesting.
The 18 thread degradation level is very surprising, it might be an anomaly.
It'd be great if later you could verify no other activity on the system.
2010/6/10 Jim Dempsey <jim at quickthreadprogramming.com>
> Chris and others:
> I got some time on a Dell R610 with dual Intel Xeon 5570 processors.
> The readers of this mailing list might find it of interest.
> Results from running fluidanimate using in_500K.fluid with 100 iterations
> Runtimes using QuickThread threading toolkit:
> 1 Total time spent in ROI: 92.494s 1.0000x
> 2 Total time spent in ROI: 48.265s 1.9164x
> 3 Total time spent in ROI: 35.771s 2.5857x
> 4 Total time spent in ROI: 28.770s 3.2149x
> 5 Total time spent in ROI: 23.912s 3.8681x
> 6 Total time spent in ROI: 21.912s 4.2212x
> 7 Total time spent in ROI: 20.918s 4.4217x
> 8 Total time spent in ROI: 18.428s 5.0192x
> 9 Total time spent in ROI: 18.897s 4.8946x * note 1
> 10 Total time spent in ROI: 18.396s 5.0279x
> 11 Total time spent in ROI: 18.002s 5.1380x
> 12 Total time spent in ROI: 17.991s 5.1411x
> 13 Total time spent in ROI: 17.946s 5.1540x
> 14 Total time spent in ROI: 16.071s 5.7553x
> 15 Total time spent in ROI: 16.057s 5.7604x
> 16 Total time spent in ROI: 14.398s 6.4241x
> 17 Total time spent in ROI: 41.042s 2.2536x ** note 2
> 18 Total time spent in ROI: 553.489s 0.1671x ** note 3
> Each processor has 4 cores with HyperThreading
> Total of 8 cores and 16 hardware threads
> fluidanimate is a floating point and memory access intensive application.
> Note 1:
> On this configuration, QuickThread distributes work to cores first, then
> back fills to HyperThread siblings second.
> Result being fairly steady slope from 1 thread to 8 threads (full set of
> cores) then shallower slope as the HT threads are filled in.
> Note 2:
> At 17 threads we have oversubscription of threads. Note the adverse effect
> on cache.
> Note 3:
> At 18 threads, the adverse effect on cache appears to be exponential.
> Additional run data would provide some insight as would profiling.
> The above results were from one set of test runs on a remote system.
> IOW I could not verify no other activity was present on the system.
> Jim Dempsey
> parsec-users mailing list
> parsec-users at lists.cs.princeton.edu
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