On Thu, Apr 24, 2014 at 4:32 PM, Dirk Eddelbuettel <[email protected]> wrote: > > Scott, > > My first quick hunches are a) 50% is too much for compiler switches, b) your > examples shows R code, and c) are you sure you are using the same BLAS?
Thanks for the quick reply Dirk and for the suggestions. As for BLAS, yes I believe I'm using the same BLAS. The output of the following two commands is the same (except for the memory addresses of course): $ ldd /usr/local/lib/R-devel/lib/R/bin/exec/R $ ldd /usr/lib/R/bin/exec/R And executing $ lsof -p <PID> | grep 'blas\|lapack' also returns the same output for both Rs: R 13017 scott mem REG 8,1 9142768 2097161 /usr/lib/atlas-base/atlas/liblapack.so.3.0 R 13017 scott mem REG 8,1 3776592 2097162 /usr/lib/atlas-base/atlas/libblas.so.3.0 I profiled and it seems that all of the R functions are slow (I can post the output if anyone is interested). I rebuilt with -O3 in CFLAGS and this improved things a lot. Time went down from 10 seconds to 5.7 or so. I reprofiled and again the R functions of R-devel seem just a tad slower across the board (I can send output if interested). Below are some timings comparing the optimized R-devel to R. $ time R-devel CMD BATCH mwe.R real 0m5.755s user 0m5.678s sys 0m0.079s $ time R CMD BATCH mwe.R real 0m5.453s user 0m5.371s sys 0m0.054s Rerunning the above commands multiple times gives about the same output. There's still a .3 second difference and I'm curious to know why. Any ideas? Scott -- Scott Kostyshak Economics PhD Candidate Princeton University _______________________________________________ R-SIG-Debian mailing list [email protected] https://stat.ethz.ch/mailman/listinfo/r-sig-debian
