Everyone, I am running R 2.4.1 on the new 8-core Mac Pro with the parSapply function from the Snow package. Tests using 2,4, and 8 threads with makeCluster() yield somewhat disappointing results. The 4 thread process is fastest. With 8 threads, all the cores max out at about 70% power, and even then it is slower than the 4 thread process which maxes out the 4 threads at about 90-95%. This suggests the additional 4 cores on the Mac Pro do not improve performance in an embarrassingly parallel R/Snow environment...
The function I tested in parSapply runs a regression (a call to "lm"). I am using Snow/rpvm package combination. There is no issue of limited memory. There are over 3 gigs of free RAM in the tests. Does anyone have suggestions as how to get more power out of a multi-core Mac Pro machine and/or have 4-core/8-core R multi-thread computing performance benchmarks/experiences to share? Thanks in advance, David David Marra Principal A.T. Kearney (Tokyo) _______________________________________________ R-SIG-Mac mailing list [email protected] https://stat.ethz.ch/mailman/listinfo/r-sig-mac
