On Tue, Oct 23, 2012 at 6:01 PM, Darren Cook <[email protected]> wrote: >> What gives? What I found that does speed up the code dramatically >> is the -march switch. I guess that can't be repo-ed because it is >> CPU dependent, right? Here's the important settings that I used to >> compile R from source: >> >> CC="gcc" >> CFLAGS="-g -O2 -march=amdfam10" >> CXX="g++" >> CXXFLAGS="-g -O2 -march=amdfam10" >> >> With these settings... >> >> MCMC Code Switches Relative Time >> R none or -O2 1.0 >> RcppEigen none or -O2 0.09 >> R -O2 -march=amdfam10 0.5 >> RcppEigen -O2 -march=amdfam10 0.013 > > Wow, those are huge differences. Am I misreading, or does that say > RcppEigen runs *seven* times quicker with the -march=amdfam10 option? > > Can that be explained? (e.g. does the AMDFAM10 processor have some > feature that speeds it up 7 times in ideal conditions?)
Eigen does use SSE2 and SSE3 pipelined instructions when they are determined to be available. _______________________________________________ Rcpp-devel mailing list [email protected] https://lists.r-forge.r-project.org/cgi-bin/mailman/listinfo/rcpp-devel
