relative performance of different interactive terminals

[Jonathan T. <jt...@as...>]

Ethan Merritt <merritt@u.washington.edu> writes:
> Or maybe hardly anyone is using x11 anymore.  I know I strongly prefer
> either wxt or qt to the x11 terminal.  I'm not saying we shouldn't fix
> this if possible, but the reality is that I view the x11 terminal as having 
> been superseded by newer, more capable terminal options.  There
> are many things that it just doesn't handle very well (font scaling,
> non-ascii encodings, transparency, anti-aliasing, ...).

Dima Kogan <gn...@di...> replied
> My only reason for sticking with x11 is performance. Last year I tried
> wxt and qt, and they were both noticeably more sluggish. I just tried it
> again, and while qt was very slow, wxt seemed about as fast as x11. So
> maybe I'll jump ship too in a bit.

On my computer wxt is subjectively *much* more sluggish than x11.
I just tried a quantitative performance test (details below), and wxt
was about a factor of 3 slower than x11 when interactively rotating
the 'splot' of a medium-sized data file.

It's interesting that the relative performance of wxt vs x11 differs
so much from one system to another.  I don't know whether this is the
underlying graphics hardware/acceleration, some feature(s) of the
different X servers used by wxt vs x11, or what.

It would be interesting to run such performance tests on a range of
different systems and see how the relative performance of different
terminals varies from one {gnuplot version, compiler, computer system}
to another.


Details of my performance test
==============================

This test measures the responsiveness of interactively rotating the
'splot' of a medium-sized data file.  The data file can be downloaded at
   http://www.astro.indiana.edu/~jthorn/spool/gnuplot-speed-test.dat
The file contains is a bit under 1/2 megabyte in size, and contains
16791 lines (16310 non-blank non-comment); each line containing 4 columns
of data (of which only the first 3 are used in this test).

The actual performance test is to enter the gnuplot commands
   set terminal ....
   unset hidden3d
   set style data lines
   splot 'gnuplot-speed-test.dat'
then enlarge the terminal window to a size of about 1200 x 1000 pixels,
and then interactively rotate the 3-D plot.  Measure the frequency of
updates by dragging the mouse (i.e., rotating the plot) continuously for
10 seconds and counting the number of times the plot updates.  If you
have a rapidly-updating CPU-usage meter, you can watch it to see what
fraction of the (a) CPU gnuplot and its outboard terminal driver are
using.


Test results
============
I'm using
>         G N U P L O T
>         Version 4.6 patchlevel 0    last modified 2012-03-04 
>         Build System: OpenBSD amd64

> Compile options:
> -READLINE  +LIBREADLINE  -HISTORY  
> -BACKWARDS_COMPATIBILITY  +BINARY_DATA  
> +GD_PNG  +GD_JPEG  +GD_TTF  +GD_GIF  +ANIMATION  
> -USE_CWDRC  +X11  +X11_POLYGON  +MULTIBYTE  +X11_EXTERNAL +USE_MOUSE  +HIDDEN3D_QUADTREE  
> +DATASTRINGS  +HISTOGRAMS  +OBJECTS  +STRINGVARS  +MACROS  +IMAGE  +USER_LINETYPES +STATS 

compiled with gcc 4.2.1 -O2.  I'm run the tests on a Lenovo Thinkpad
T60 laptop, Intel Core 2 T7200 dual-core cpu locked at its minimum clock
rate of 1.0GHz (this makes timing easier), ATI Radeon Mobility X1400
graphics, running OpenBSD 5.1-stable.

On my computer, x11 updates this plot between 26 and 28 times in 10 seconds
(using about 70-80% CPU on one core), while wxt updates around 8 or 9
times in 10 seconds (using about 100% CPU on one core).

ciao,

-- 
-- "Jonathan Thornburg [remove -animal to reply]" <jt...@as...>
   Dept of Astronomy & IUCSS, Indiana University, Bloomington, Indiana, USA
   on sabbatical in Canada starting August 2012
   "Washing one's hands of the conflict between the powerful and the
    powerless means to side with the powerful, not to be neutral."
                                      -- quote by Freire / poster by Oxfam