[Plplot-devel] Master default build issue SOLVED (but Linux wxwidgets inefficiency not solved)

[Alan W. I. <ir...@be...>]

On 2015-12-29 17:48-0000 Phil Rosenberg wrote:

> Hi Alan
> I think this should be fixed. I don't have easy access to a Linux box
> right now, but I have tested and the new version builds with gcc on
> Cygwin.

Hi Phil:

I confirm the build of the master tip (as of commit 36bd058 Fix
compile error for wxPLplotwindow for gcc) now works again on Linux, and the
build of the test_c_wxwidgets target also shows no run-time issues.

Thank you for quickly addressing this default build issue for master
tip.

You asked me off list to perform some Linux timing tests of your
latest code version.

Here are the latest results for the xwin, xcairo, qtwidget, and
wxwidgets devices for the interactive test_c_<interactive device> targets
which generate interactive results for the 01 04 08 14 16 24 30 C
examples (note these targets were temporarily modified for these tests
to exclude example 17 since that is much slower than all the rest and
particularly slow for xcairo and qtwidget so in any case we always drop
it from the list for those devices, see
plplot_test/test_c_interactive.sh.in):

software@raven> time make -j4 test_c_xwin >& /dev/null

real    0m2.896s
user    0m1.152s
sys     0m0.348s
software@raven> time make -j4 test_c_xcairo >& /dev/null

real    0m4.514s
user    0m3.556s
sys     0m0.392s
software@raven> time make -j4 test_c_qtwidget >& /dev/null

real    0m3.144s
user    0m1.688s
sys     0m0.372s
software@raven> time make -j4 test_c_wxwidgets >& /dev/null

real    0m26.273s
user    0m1.108s
sys     0m0.344s

In all cases the tests were done two or more times to build all
prerequisites and get everything into memory for the early tests
while only the last test result is reported above.

So there is still roughly an order of magnitude of inefficiency on
Linux for wxwidgets compared to the other devices which to my mind is
just barely acceptable.  My cpu meter and also the comparison of real
and user times for the above results indicates most of that time is
spent waiting rather than executing cpu instructions which is why I
suspect some badly tuned aspect of the Linux IPC between application
and wxPLViewer that generates inordinate amounts of wait time is still
the principal cause of these bad efficiency results for wxwidgets on
Linux.

For the MSVC case can you similarly compare speed results (excluding
example 17, see plplot_test/test_c_interactive.sh.in to see where to
exclude that example from the list of examples) for the test_c_wingcc
target and the test_c_wxwidgets target?  If those two times are
comparable to each other, then my working hypothesis to explain these
results is the Windows IPC is well tuned, but that is not the case for
the Linux IPC method that you are currently using.  On the other hand,
if test_c_wingcc is an order of magnitude faster, perhaps the Windows
IPC method is equally badly tuned, and you can find some common
factor to speed that up as well as the Linux IPC method.

Alan
__________________________
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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