Path: utzoo!utgpu!news-server.csri.toronto.edu!rpi!zaphod.mps.ohio-state.edu!samsung!uunet!xzaphod!michael
From: michael@xzaphod.uucp (Michael R. Miller)
Newsgroups: comp.windows.x
Subject: Re: X server speed
Keywords: speed
Message-ID: <1991Jun01.202725.6560@xzaphod.uucp>
Date: 1 Jun 91 20:27:25 GMT
References: <1991May30.210439.10218@casbah.acns.nwu.edu>
Reply-To: michael@xzaphod.UUCP (Michael R. Miller)
Organization: XZaphod in Rockville, MD
Lines: 44

In article <1991May30.210439.10218@casbah.acns.nwu.edu> edy@andersen.com (Edy Liongosari) writes:
>I am wondering whether any body out there has done any performance testing
>of X in Sun Sparc workstations.
>
>I've tried to draw circles; each circles has radius = 100 pixels and
>line width = 1. It takes about 80 sec to draw 3,600 circles using Sun Sparc 1+ 
>with Graphics Accelerator board (or 45 circles/sec).
>
>Is there any trick to increase the performance? 
>
>Thanks in advance
>-Edy

Try drawing the circle once into a bitmap or pixmap and then XCopyArea the
offscreen circle to your onscreen location.  If the color is the same, a
pixmap might be better.  If the circles overlap, you can use a bitmap and
do some kind of stippling operation (perhaps GXcopy or GXor?) of the bits
onto the screen.

If you use stippling or tiling, try setting up between 8 and 32 different
pixmaps each with it's own GC all set up and ready to use.  Then decide
which GC to use based upon how your x coordinate modulo {8 or 32} would
select a GC (build an N entry table of GCs each with its tile/stipple
offset 1 pixel greater than the previous).  Your area stippled/tiled is
equal to the size of the bitmap/pixmap.  Stippling will allow you to use
different colors (make sure you set the current foreground in the GC before 
you draw).  Stippling will be slower than tiling because your GC must be
re-validated every time you change the FG value.  A good server will detect
that the stipple rotation didn't change and won't go thru the effort of
redoing the origin of the stipple bitmap.  But that's a good server.

Tiling is the best but most restrictive.  Tiling can get you bitblt speeds
which should be significantly faster than 45 circles/second.  A plain old
XCopyArea will be somewhat slower as the server will have to line up the
source and destination but you should still do quite well with that.
Stippling will probably fall in between the two in speed and much of that
performance will be dependent upon the quality of the GC validation routine
and the characteristics of your application (ie. how many times you must
change the FG value in your GCs).

Good luck.

Michael R. Miller
uunet!xzaphod!michael