On 06/30/10 09:01 PM, Nils Bruin wrote:
Setting ulimits is generally a good idea, because excessive memory use is usually a sign of a bug, and it is better if the program crashes before it forces the system to thrash its swapspace (especially on multi-user machines)One can set "soft" ulimits, which are generally the right thing: The user can increase them if he really needs to, but is otherwise protected. Indeed, setting the virtual memory ulimit too low will cause sage to fail starting up. Apparently, 10^5 kib is too small for sage, which is fine: sh-3.2$ ulimit -S -v 100000 sh-3.2$ ulimit -v 100000 sh-3.2$ sage ---------------------------------------------------------------------- | Sage Version 4.4.4, Release Date: 2010-06-23 | | Type notebook() for the GUI, and license() for information. | ---------------------------------------------------------------------- [...] ImportError: /usr/local/sage/4.4.4/local/lib/python2.6/lib-dynload/ fcntl.so: failed to map segment from shared object: Cannot allocate memory However, if we set a more reasonable bound (10^6 kib, roughly a gig), sage does start up without problem, but as you can see, it wipes the soft virtual memory limit! sh-3.2$ ulimit -S -v 1000000 sh-3.2$ ulimit -v 1000000 sh-3.2$ sage ---------------------------------------------------------------------- | Sage Version 4.4.4, Release Date: 2010-06-23 | | Type notebook() for the GUI, and license() for information. | ---------------------------------------------------------------------- sage: import os sage: os.system("ulimit -v") unlimited 0 Is this intentional? Does someone know how to turn this off? Our students and the people who share computers with them greatly benefit from programs crashing quickly instead of bothering other people.
It seems dumb if Sage is overwriting those limits. It would be more sensible to report they are too low if Sage feels it needs more than what the limits are set to.
I came across this patch http://trac.sagemath.org/sage_trac/attachment/ticket/4332/trac4332.patch suggesting the ulimit was not changed See also http://trac.sagemath.org/sage_trac/ticket/2695 FYI, drkir...@hawk:~$ ulimit -S -v 100000 drkir...@hawk:~$ math Mathematica 7.0 for Sun Solaris x86 (64-bit) Copyright 1988-2009 Wolfram Research, Inc. In[1]:= t=Table[Prime[i],{i,1,10^6}] No more memory available. Mathematica kernel has shut down. Try quitting other applications and then retry. drkir...@hawk:~$ Dave -- 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
