On Thu, 11 Mar 2010 00:41:16 +0000, "Dr. David Kirkby" <david.kir...@onetel.net> wrote: > > > > NUM_THREADS=10 > > in makefile. Then I issued "make ptestlong", only to see that cddlib > > was reinstalled. Doctesting is still running in parallel using 10 > > threads. > > I've not tried a parallel ptestlong myself. I'll see what happens on one of > my > machines. I can't see why cddlib would be reinstalled. > > It is probably worth using far more than 10 threads on 't2'. Although it has > 16 > core, there are 128 hardware threads. I've convinced myself that one needs to > use at least 256 threads to get optimal performance. In fact, going to 1000 > threads is very slightly quicker. > > I think I posted some benchmarks I'd done before on 't2', and quite simply > setting threads=cores does not give anywhere near the performance possible. > Of > course, you don't want to bring 't2' to its knees, but it is not heavily used. >
We have to be careful here and experiment some more before recommending a number. A couple of weeks ago I tried make ptestlong with 100 threads on t2 and had to eventually kill everything in sight manually to avoid disaster :). Best, Alex -- Alex Ghitza -- http://aghitza.org/ Lecturer in Mathematics -- The University of Melbourne -- Australia -- To post to this group, send an email to sage-devel@googlegroups.com To unsubscribe from this group, send an email to sage-devel+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URL: http://www.sagemath.org
