Also you might want to try out this which will repeatedly run your benchmarks to average out the values and make comparisons easier:
http://rbenchmark.googlecode.com On Sat, Feb 27, 2010 at 11:55 PM, Gabor Grothendieck <ggrothendi...@gmail.com> wrote: > The last component seems the most meaningful since its the amount of > time you actually waited for the code to run. > > On Sat, Feb 27, 2010 at 11:44 PM, Ravi Varadhan <rvarad...@jhmi.edu> wrote: >> >> Thanks, Gabor. Your reply is helpful, but it still doesn't answer whether I >> should use the sum of the first two components of system.time (user + system >> CPU) or only the first one (user CPU). >> >> Ravi. >> ____________________________________________________________________ >> >> Ravi Varadhan, Ph.D. >> Assistant Professor, >> Division of Geriatric Medicine and Gerontology >> School of Medicine >> Johns Hopkins University >> >> Ph. (410) 502-2619 >> email: rvarad...@jhmi.edu >> >> >> ----- Original Message ----- >> From: Gabor Grothendieck <ggrothendi...@gmail.com> >> Date: Saturday, February 27, 2010 9:47 pm >> Subject: Re: [R] Which system.time() component to use? >> To: Ravi Varadhan <rvarad...@jhmi.edu> >> Cc: r-help@r-project.org >> >> >>> Try this: >>> >>> > system.time(Sys.sleep(60)) >>> user system elapsed >>> 0.00 0.00 60.05 >>> > pt <- proc.time(); Sys.sleep(60); proc.time() - pt >>> user system elapsed >>> 0.00 0.00 60.01 >>> >>> On Sat, Feb 27, 2010 at 9:33 PM, Ravi Varadhan <rvarad...@jhmi.edu> wrote: >>> > >>> > Hi, >>> > >>> > The `system.time(expr)' command provide 3 different times for >>> evaluating the expression `expr'; the first two are user and system >>> CPUs and the third one is total elapsed time. Suppose I want to >>> compare two different computational procedures for performing the same >>> task, which component of `system.time' is most meaningful in the sense >>> that it most accurately reflects the computational effort of the >>> algorithm, and does not depend upon the idiosyncrasies of the >>> operating system. >>> > >>> > I have always been using the first component of `system.time', which >>> is the user CPU. Should I use the sum of user and system CPU or is >>> the total elapsed time a better measure? I would appreciate UseR's >>> feedback on this. >>> > >>> > Thanks very much. >>> > >>> > Best, >>> > Ravi. >>> > ____________________________________________________________________ >>> > >>> > Ravi Varadhan, Ph.D. >>> > Assistant Professor, >>> > Division of Geriatric Medicine and Gerontology >>> > School of Medicine >>> > Johns Hopkins University >>> > >>> > Ph. (410) 502-2619 >>> > email: rvarad...@jhmi.edu >>> > >>> > ______________________________________________ >>> > R-help@r-project.org mailing list >>> > >>> > PLEASE do read the posting guide >>> > and provide commented, minimal, self-contained, reproducible code. >>> > >> > ______________________________________________ R-help@r-project.org mailing list https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.