cflatter@ZIA.AOC.NRAO.EDU (Chris Flatters) (09/29/90)
I just hacked my image display application around so that it buffers the image in a pixmap and uses this to refresh the window. When the application was refreshing the window from an XImage structure in the client, it took about 1.5 seconds to refresh a 1024 by 720 pixel 8-bit window. Using the pixmap it is so fast that I can't time it (I guess about one tenth of a second) so it looks as though the reason I didn't see any speed improvements from the GX board on a SPARCstation 1 for XPutImage is that the bottleneck is the transfer of the image data from the client to the server. The moral of the story appears to be: if you have an image processing application and a GX board you will get a substantial gain in performance by storing the image as a pixmap. This is probably true of any graphics accelerator on any workstation. I guess that it might also increase the performance on an unaccelerated workstation. Of course you have to balance this against the possibility of increased paging due to the extra memory used by the server or the possibility that you may exceed memory limits on some servers. Chris Flatters