On Jan 13, 3:05 pm, Jason Grout <jason-s...@creativetrax.com> wrote:
> mabshoff wrote:

<SNIP>

> > This is not how this works, i.e. a lot of the memory Sage uses is
> > shared mappings between libraries, so the first notebook process is
> > much, much more expensive than subsequent ones. top and the default
> > interface it uses on Linux is dumb regarding shared mappings, i.e.
> > every notebook process is reported to use every library that is
> > dlopened by Sage.
>
> Okay, I was using top to calculate this.  What is a better way to
> calculate the actual memory being used?  I'd like to have an accurate
> idea of the memory requirements of a big Sage server.

smap and pmap comes to mind. Some pointers to get started:

 * 
http://virtualthreads.blogspot.com/2006/02/understanding-memory-usage-on-linux.html
 * http://bmaurer.blogspot.com/2006/03/memory-usage-with-smaps.html

The slashdot discussion at

 * http://it.slashdot.org/article.pl?sid=06/02/06/120210

also has some lively discussion, but the signal to noise ratio is
pretty bad or normal for slashdot :)

Note that smap has Python binding for Linux, so we might want to
consider using that optionally since not every kernel supports it,
even though on modern system I would guess it will be hard to find one
that doesn't.

In general we are using crappy interfaces to measure memory
consumption from Sage, i.e. get_memory_usage(). We are even parsing
the output from "top" on non-Linux platforms!

> Thanks,
>
> Jason

Cheers,

Michael
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