Andy: The short answer is yes, and we saw huge speedups. My latest post, as well as Lee's, has details.
On Friday, December 7, 2012 9:42:03 PM UTC-5, Andy Fingerhut wrote: > > > On Dec 7, 2012, at 5:25 PM, Lee Spector wrote: > > > > > Another strange observation is that we can run multiple instances of the > test on the same machine and (up to some limit, presumably) they don't seem > to slow each other down, even though just one instance of the test appears > to be maxing out all of the CPU according to "top". I suppose that means > that "top" isn't telling me what I thought -- my colleague says it can mean > that something is blocked in some way with a full instruction queue. But > I'm not interested in running multiple instances. I have single > computations that involve multiple expensive but independent > subcomputations, and I want to farm those subcomputations out to multiple > cores -- and get speedups as a result. My subcomputations are so completely > independent that I think I should be able to get speedups approaching a > factor of n for n cores, but what I see is a factor of only about 2 on > intel machines, and a bizarre factor of about 1/2 on AMD machines. > > Lee: > > When you say "we can run multiple instances of the test on the same > machine", do you mean that, for example, on an 8 core machine you run 8 > different JVMs in parallel, each doing a single-threaded 'map' in your > Clojure code and not a 'pmap'? > > And what kinds of speedups does that achieve? > > The results could help indicate whether the problem you are seeing is due > to the hardware/OS, or something about multiple threads within a single > JVM. > > Andy > > -- You received this message because you are subscribed to the Google Groups "Clojure" group. To post to this group, send email to clojure@googlegroups.com Note that posts from new members are moderated - please be patient with your first post. To unsubscribe from this group, send email to clojure+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/clojure?hl=en
