On Sun, 2008-12-28 at 03:14 +0000, Peter Clifton wrote: > Hi guys, > > I'm not sure this is specific to the invalidate / expose model stuff, or > the cairo code. I suspect not, however I've been seeing some real > performance problems dragging around components with lots of text with > the current git HEAD code. > > I've tracked this down to the fact that the path in my Xorg server which > is being hit for lines produced with gdk_draw_line() is not accelerated > for non-horizontal / non-vertical lines (using the default "EXA" > acceleration architecture in the X server). > > (EXA has been default for a while now, although I can't remember what X > server / Intel driver combination made that the case). I'm not sure what > other drivers will be like, but I think the issues is the core EXA code.
> It seems that the particular combination of X server + Intel driver > which I'm running (quite new, and not stable yet), incurs a severe > performance penalty for pixmap migration, so I'm really noticing this > non-accelerated path when we draw lots of little lines for text. (I > don't notice it when using the development gschem + pango code which > uses accelerated paths for drawing glyphs). Update: The tip of the 2.6 branch for the Intel 2D video driver has cured the performance problems I was noting with the old code. Since EXA rendering of lines is not hardware accelerated, if you're Xorg server is using EXA acceleration the performance you'll get is CPU dependent and dependant on the cost of migrating data between the GPU and the CPU. I'd be interested to hear whether gschem testers notice any performance differences with the code for cairo rubberbanding / moving of objects, which is landing soon. Best regards, -- Peter Clifton Electrical Engineering Division, Engineering Department, University of Cambridge, 9, JJ Thomson Avenue, Cambridge CB3 0FA Tel: +44 (0)7729 980173 - (No signal in the lab!) _______________________________________________ geda-dev mailing list geda-dev@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-dev
