Re: gEDA-user: Ben mode feature request

[Peter Clifton <pcjc2@xxxxxxxxx>]

On Sun, 2010-10-31 at 20:49 +0100, kai-martin knaak wrote:
> Peter Clifton wrote:
> 
> > /me goes back to writing kernel profiling driver for intel GPUs to
> > squeeze more framerate out of PCB+GL.
> 
> Side note: I just purchased a used  ATI Radeon HD 4670 that free3d.org 
> announces as the fastest card with open sourced drivers. I'll keep you 
> posted on my mileage.
> 
> What kind of acceleration does your GL enabled version actually use?
> XAA, EXA, UXA ... just some buzz acronyms I got from the guy who 
> recommanded the ATI card to me. 

None really.. (because they are 2D acceleration APIs in the X server). 

My machine uses UXA, which is the X server acceleration technique used
by Intel drivers. (Only Intel IIRC). UXA was originally based on EXA,
which was designed to accelerate XRender operations. Cairo uses XRender,
so EXA (should) be good with Cairo, and a modern desktop. UXA shares
that benefit.

XAA is the older X acceleration API, designed to accelerate traditional
X operations such as blits / line drawing.. basically our old 2D drawing
stuff.

This is one of the reasons why PCB / gschem got slower on modern
hardware and Xservers, that the old XAA APIs which were designed to
accelerate those "old" kind of drawing operations were phased out in
favour of acceleration APIs tailored to modern drawing APIs.

UXA + DRI2 + GEM play together nicely on Intel.

On Radeon / Nouveau open source drivers, I think it is something along
the lines of:

EXA + DRI2 + TTM. (Although I'm not 100% sure).

DRI2 is the kernel / X11<->application interface, and GEM/TTM are in
kernel graphics memory / buffer managers.


I should probably push my latest experimental changes for speed in a
separate branch and let you compare the "old "PCB+GL for one which uses
more modern rendering techniques such as VBOs and a pixel shader.

-- 
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!)
Tel: +44 (0)1223 748328 - (Shared lab phone, ask for me)



_______________________________________________
geda-user mailing list
geda-user@xxxxxxxxxxxxxx
http://www.seul.org/cgi-bin/mailman/listinfo/geda-user