On Sun, Mar 29, 2009 at 11:34 AM, Peter Jeremy <peterjer...@optushome.com.au> wrote: > On 2009-Mar-28 14:53:46 -0700, Ondrej Certik <ond...@certik.cz> wrote: >>I am trying to figure out the best way to automatically determine the >>number of processors and used that information to speed up Sage build. > > Note that this should be able to be over-ridden by the operator - > just because a system has (say) 8 cores available doesn't mean that > the sage build should use them all.
Yes, exactly. I am still thinking of the best way to do that. I think the default should be to just use one processor, but it should be easy to tell it to use all processors, or just certain amount of them. I think I will just add more targets to the makefile in the top directory, e.g. something like make # use 1 processor make parallel # use all processors JOBS=3 make # use 3 processors > >>If Python is not available, then I can use this simple C program: >> >>http://github.com/certik/sysconf/blob/master/ncpus.c >> >>but I suspect this will not work on Mac or Windows. > > sysconf() is part of POSIX so it should work in any POSIX environment. > Microsoft made a big claim about Windows being POSIX compliant so it > should work there - but may need to link against special libraries. > It should work on OS-X (though I can't test it). > >>2) try: cat /proc/cpuinfo | grep processor | wc -l > > That is far less portable than sysconf() because it _only_ works > on Linux, whereas sysconf() should work on nearly all Unix systems > (and some others). Yes, indeed, I found out that sysconf() does work on Mac. So that's awesome. Ondrej --~--~---------~--~----~------------~-------~--~----~ To post to this group, send email to sage-devel@googlegroups.com To unsubscribe from this group, send email to sage-devel-unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sage-devel URLs: http://www.sagemath.org -~----------~----~----~----~------~----~------~--~---
