On Wed, Aug 8, 2012 at 6:18 PM, Eberle, Anthony <ae...@allstate.com> wrote: > I have a question about multiple cores and CPU's for running R. I've > been running various tests on different types of hardware and operating > systems (64 bit, 32 bit, Solaris, Linux, Windows, RV.10, .12, .15, > .15.1.) Generally speaking, it seems that for a single user and process > that R prefers to have as much resources as possible; especially memory. > > I've looked at some of the r-sig groups and it seems most threads about > multicore or CPU's have to deal with using packages like parallel or > snow or something such as this and leaving it up to the user what can be > parallelized and how which makes perfect sense to me. > > The question I have is about what the advantage of machines with > multiple cores or CPU's. To me, it seems that until R is parallelized > (or if I am writing my own code that can run in a parallel fashion) that > a single user and single (non-parallel) process would work just as fine > on a single core, single CPU box as it would on (for example) a quad > core with 24 threads? Is my observation off or am I missing something? > Of course, I know there are other "things" going on with most modern > systems such as operating system and other processes that in practice > affect this observation a bit. In addition if I had a R environment > where multiple people were logging in and running R queries that would > likely gain from multiple CPU's and a multitasking OS I'm assuming.
To a first approximation, I believe that is correct if you are doing nothing else on the computer. If you are, it's nice to have that second core around :-) Note however, that it's very easy to write parallelizable code with R since every *apply() statement is trivially parallelizable. The more difficult question is asking yourself whether the overhead of parallelizing is worth it (and that's a much harder question) Best, Michael > > I'm just trying to get a feeling and validate what I think I am seeing. > Thoughts and comments are appreciated. > > > Thanks, > > Anthony > > [[alternative HTML version deleted]] > > ______________________________________________ > 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. ______________________________________________ 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.
