On Monday, May 5, 2014 5:32:28 PM UTC-7, William wrote:
>
> On Mon, May 5, 2014 at 5:07 PM, John H Palmieri
> <jhpalm...@gmail.com<javascript:>>
> wrote:
> >
> >
> > On Monday, May 5, 2014 4:41:39 PM UTC-7, William wrote:
> >>
> >> On Mon, May 5, 2014 at 4:16 PM, John H Palmieri <jhpalm...@gmail.com>
> >> wrote:
> >> >> -leif
> >> >>
> >> >> P.S.: If you haven't set MAKE, Sage "guesses" the number of threads
> to
> >> >> use to build the Sage library as well as the docs, AFAIK.
> >> >
> >> >
> >> > Right: Sage uses SAGE_NUM_THREADS to decide how many threads to use
> for
> >> > building spkgs and docs. If it's set to a number, that value gets
> used.
> >> > Otherwise, SAGE_NUM_THREADS gets set in src/bin/sage-env, using the
> >> > Python
> >> > program src/bin/sage-num-threads.py:
> >> >
> >> > sage_num_threads_array=(`sage-num-threads.py 2>/dev/null || echo
> 1 2
> >> > 1`)
> >> > SAGE_NUM_THREADS=${sage_num_threads_array[0]}
> >> >
> >> > This is documented in the installation manual, but maybe it should
> also
> >> > be
> >> > in the top-level README.txt.
> >>
> >> There's something confusing going on here still. I just read the
> >> source to sage-num-threads.py and it outputs 3 numbers. The first is 1
> >> by default since I didn't set any environment variables, so despite my
> >> having 12 cores, SAGE_NUM_THREADS is 1. The others are 8 and 12, but
> >> according to sage-num-threads.py those are *only* used if I explicitly
> >> request something to happen in parallel, e.g., "make ptest". To
> >> quote the docs:
> >>
> >> "2) The number of threads to use when parallel execution is
> >> explicitly asked for (e.g. sage -tp)"
> >>
> >> I definitely only typed "make test" in my clean Sage install, so I did
> >> not explicitly ask for anything to be in parallel.
> >
> >
> > Building spkgs is by parallel by default, but I think it should be
> limited
> > by SAGE_NUM_THREADS.
> >
> >>
> >> However, it looks
> >> like the doc building is in parallel anyways, which is the point when
> >> I ran out of RAM. So something seems misleading. Maybe 2 above
> >> really is
> >>
> >> "2) The number of threads to use when parallel execution is
> >> explicitly asked for (e.g. sage -tp), or when building the
> >> documentation (which is always in parallel!?)."
> >
> >
> > No: the number of threads used for docbuilding comes from
> SAGE_NUM_THREADS.
> > From src/doc/common/build_options.py:
> >
> > # Number of threads to use for parallel-building the documentation.
> > NUM_THREADS = int(os.environ.get('SAGE_NUM_THREADS', 1))
> >
> > If you do "sage --sh -c 'export $SAGE_NUM_THREADS' " then you get "1",
> > right? By the way, I searched for SAGE_NUM_THREADS_PARALLEL, and it is
> only
> > used in src/sage/doctest/control.py, the doctesting framework.
>
> Your command doesn't quite work... but yes, it's 1:
>
> salvus@salvus-base:/usr/local/sage/sage-6.2.rc2$ sage --sh -c 'export
> $SAGE_NUM_THREADS'
> /bin/bash: line 0: export: `1': not a valid identifier
> salvus@salvus-base:/usr/local/sage/sage-6.2.rc2$ sage -c
> 'print(os.environ["SAGE_NUM_THREADS"])'
> 1
>
Sorry, I meant "echo" instead of "export". Oh well.
--
John
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