I think I remembered the problems wrong. I think maybe it isn't an issue with the version of VirtualBox, but an issue with the kernel that mod.math is running. Performance with multiple cores seems to be much worse than single core performance. An example I just tried:
with a single core in the VM, time to compile gnutls: real 7m46.024s user 1m23.073s sys 4m48.342s with 4 cores in the VM, time to compile gnutls (using a single process): real 13m20.065s user 4m50.114s sys 15m43.147s (mod.math is heavily loaded right now, so maybe this isn't a completely conclusive test, but I think it is reliable.) I think that things are actually much worse than it seems with the above timings. Multicore VirtualBox seems to be basically unusable on mod.math. (I've tried this before, and had a similar experience.) It is hard for me to find reliable information from google, given the age of the OS, but there is some reference to problems here: https://www.virtualbox.org/ticket/5501. On the bug discussion, there's basically no identification of the problem other than "it goes away with a newer kernel," though. On Tue, Mar 6, 2012 at 12:20 PM, William Stein <wst...@gmail.com> wrote: > On Tue, Mar 6, 2012 at 12:11 PM, Jonathan Bober <jwbo...@gmail.com> wrote: > > I am going to be building a VM on sage.math for other purposes soon, so > I'll > > try to make one for this as well. I suppose we would want something like > > Ubuntu 11.10 32-bit desktop edition? > > > > (Unfortunately, virtualbox on the *.math machines is really old, or at > least > > it was last time I checked, so using more than one cpu, for example, > doesn't > > work. It might be nice if it could be upgraded somehow, but I imagine > that > > might be rather difficult without upgrading the OS.) > > Use mod.math instead of boxen.math. On mod.math there is a newer > virtualbox. > > > > > > > On Tue, Mar 6, 2012 at 6:23 AM, Jeroen Demeyer <jdeme...@cage.ugent.be> > > wrote: > >> > >> On 2012-03-06 15:17, Georg S. Weber wrote: > >> > I would expect that a "Linux i386" machine > >> > is mainly tested as a virtualized image (with a special "32bit" setup, > >> > of course, maybe even using SAGE_ATLAS and such). > >> This has been suggested regularly, it just needs to be done. If you are > >> able to do this, please do it! > >> > >> -- > >> 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 > > > > > > -- > > 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 > > > > -- > William Stein > Professor of Mathematics > University of Washington > http://wstein.org > > -- > 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 > -- 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
