I'm pretty sure that's not it. I'm seeing the same thing when I run it on one of the cluster machines. > On Oct 28, 2015, at 6:10 AM, Ernesto Carrella <[log in to unmask]> wrote: > > Is your RAM being the bottleneck by any chance? > >> On Wed, Oct 28, 2015 at 5:16 AM Joey Harrison <[log in to unmask]> wrote: >> I'm experimenting with the -parallel flag and finding that using 2 parallel threads is slower than a single thread, and using 3 is slower still. I have 4 cores on my machine, FYI. >> >> $ time java -jar HeatBugs.jar -for 10000 -repeat 4 -parallel 1 -quiet >> >> real 0m4.514s >> user 0m6.098s >> sys 0m0.749s >> >> $ time java -jar HeatBugs.jar -for 10000 -repeat 4 -parallel 2 -quiet >> >> real 0m4.799s >> user 0m12.019s >> sys 0m1.437s >> >> $ time java -jar HeatBugs.jar -for 10000 -repeat 4 -parallel 3 -quiet >> >> real 0m5.972s >> user 0m21.190s >> sys 0m2.933s >> >> What's the deal here? >> >> Joey