On 2017-08-08 08:44-0000 Arjen Markus wrote:

Hi Alan,

-----Original Message-----
From: Alan W. Irwin [mailto:ir...@beluga.phys.uvic.ca]
Sent: Tuesday, August 08, 2017 1:59 AM
As the full run takes half a day


The fairly equivalent test here (although I test substantially more components 
PLplot because Linux has allowed me to install virtually all of the PLplot soft
dependencies) takes ~2 hours here on a decade-old (but still fairly high end) 
cpu box with each of those cpu's running at 2.4GHz.  So I would predict it would
take roughly 4 hours there on your one-cpu box if that single cpu also runs at
roughly 2.4GHz.  So out of curiosity does your "half a day" correspond to half a
working day, i.e., 4 hours or do you mean something much longer than that?

As the laptop I use has four cores (8 hyperthreads), I would expect it to be 
faster, rather than slower. However, the wall clock time it takes may be 
determined by the starting and stopping of the many processes, not so much by 
the running of each. That is my impression at least, not based on any kind of 

So if you use make -j8 (or so) and ctest -j8 for your comprehensive
test it will really go ~4 times faster because those -j options will
utilize your four cores completely.  But you have found in the past
that the -j option gives unreliable results for both make and ctest
for both the Cygwin and MinGW-w64/MSYS2 platforms.  So you have
dropped these -j options with the result that you only use one of your
cores, but at least you do get slow but reliable results that way.

It just struck me that the other possibility is using all four cores
really heats up your computer, and if you haven't had a recent dust
cleanout that excess heat could cause hardware glitches.  So that
might have been the source of the previous unreliability you had with
-j options. So if your system guy was willing to blow out the dust on
your computer, then you might want to try -j8 again (for both make and

Alan W. Irwin

Astronomical research affiliation with Department of Physics and Astronomy,
University of Victoria (astrowww.phys.uvic.ca).

Programming affiliations with the FreeEOS equation-of-state
implementation for stellar interiors (freeeos.sf.net); the Time
Ephemerides project (timeephem.sf.net); PLplot scientific plotting
software package (plplot.sf.net); the libLASi project
(unifont.org/lasi); the Loads of Linux Links project (loll.sf.net);
and the Linux Brochure Project (lbproject.sf.net).

Linux-powered Science

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