[parsec-users] Freqmine question

Raghav Mohan rmohan2 at wisc.edu
Wed Aug 8 13:20:02 EDT 2012


Hi,

I am trying to parallelize the Freqmine(parsec v 2.1) benchmark with my own parallel library instead of Open MP. I ran the freqmine benchmark and compared the results from the sequential to open MP version. I would expect the Open MP time to be drastically less, however, it keeps increasing by the magnitude of threads. (Essentially reverse speedup). I am running freqmine on a Hyper threaded Intel Xeon E5620 CPU. This machine has 8 cores that are hyperthreaded, giving 16 threads. Here are the sample results:


Command: 
./freqmine kosarak_250k.dat 220 out.txt 



Sequential Version Result : 
the data preparation cost 0.163102 seconds, the FPgrowth cost 2.720993 seconds


OMP Version Result (16 threads): 
the data preparation cost 0.191582 seconds, the FPgrowth cost 9.168250 seconds




As one can see, the FPgrowth cost for the threaded is about 4 times more than the sequential. This is the behavior is replicated for all inputs.


I apologize if I am missing something or interpreting the results wrongly, and this is the expected behavior, however, I read the manual, and I could not find any information on this.
Any help provided is more than greatly appreciated.


Thank you.


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