I upgraded from FedoraCore4 (which has provided me good service for many years) to Fedora12.  In doing so there were some obvious performance and rendering differences that I could consider to be regressions.

In this bug report is to concentrate on describing the performance differences, after consultation with the good folk on irc:freenode/#radeon I ran some x11perf tests to highlight the issues and provide real numbers of my experience.

Overall many tests have gotten a few %  (between 5 and 15%) over the past 5 years, however some of the worst regressions have gotten 20 times slower.  Particulating relating to.


To explain the testing setup, it was exactly the same hardware, the X11 server was started manually and free standing while the system was in a low runlevel (in some cases 1/single-user).  Same LCD monitor, same resolution, same 64bit variety of OS/Xorg/drivers.  The tests were then run and the output logged.

The 2005 versions are Xorg 6.8.3, Kernel 2.6.9-22.ELsmp x86_64, using UMS.

The 2010 version is Xorg 1.7.6 with xorg-x11-drv-ati-6.13.0-0.21.20100219gite68d3a389.fc12.x86_64, Kernel 2.6.32.11-99.fc12.x86_64 using KMS.


The tests which have regressed and are the most critical (and the focus of this bug report) are:

WORSE -95% CRITICAL REGRESSION
6.8.2:     900 reps @   5.7020 msec (   175.0/sec): Scroll 500x500 pixels
1.7.6:      50 reps @ 108.3004 msec (     9.2/sec): Scroll 500x500 pixels

WORSE -42% CRITICAL REGRESSION
6.8.2:    1200 reps @   5.3795 msec (   186.0/sec): Copy 500x500 from pixmap to window 
1.7.6:     800 reps @   9.2924 msec (   108.0/sec): Copy 500x500 from pixmap to window

WORSE -95% CRITICAL REGRESSION
6.8.2:    1200 reps @   5.4315 msec (   184.0/sec): Copy 500x500 from window to pixmap 
1.7.6:      80 reps @ 109.8940 msec (     9.1/sec): Copy 500x500 from window to pixmap