benchmarks suck on 8 core i7

guruofquality / gras

GRAS: The GNU Radio Advanced Scheduler

https://github.com/guruofquality/gras/wiki

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benchmarks suck on 8 core i7 #45

Closed guruofquality closed 11 years ago

guruofquality commented 11 years ago

this could be due to bad scheduling since we are spinning...

The benchmarks do improve when I numactl --physcpubind="0,1,2,3"

guruofquality commented 11 years ago

dual quad core opteron - good - http://i.imgur.com/r2ihYwe.png 8 core i7 - bad - http://i.imgur.com/lp0RN1M.png

guruofquality commented 11 years ago

turns out we were unfairly handicapping gras with small chunk sizes. The GR chunk sizes is 32kiB by default, and GRAS was defaulting to 16kiB. The i7 happened to be so fast that scheduler overhead was dominating the work overhead, since 1/2 chunk size means double the scheduler overhead. Making GRAS the same chunksize basically addresses this. Close bug when new plots uploaded.

guruofquality commented 11 years ago

Still not 100% happy, but the chunksize was the real issue for this bug. I will make a new one for general benchmark improvements.