Not solved! (was Re: client-side font rendering very very slow in X.org xserver 1.5.3 w/r200: massive fetches from VRAM, why?)

[Nix]

I said:
> 1.5: EXA, 16,     AA: dixLookupPrivate 23.17
>                       generally much faster than XAA, occasionally degrades to
>                       XAA speed
> 1.5: EXA, 24,     AA: dixLookupPrivate 26.83
> 1.6: EXA, 16,     AA: exaBufferGlyph 5.74 (X: 49.42); xterm: 9.48; kernel: 20.10
>                       *********************************************************
>                       ***********************
> 1.6: EXA, 24,     AA: exaBufferGlyph 4.82 (X: 57.88); xterm: 7.09, kernel: 33.5
>                       App speed: 50, considerably slower than 16bpp. X seems to
>                       be spending longer in the kernel.
>                       **************************************************

These lovely results continued for about a day, then abruptly hit a
wall. Text rendering is now as slow as it ever was, or slower, taking
five seconds or so to repaint the screen once in order to scroll down a
single line :((( e.g. doing a CPAN upgrade, the top few lines of
sysprof are:

[perl]                29.90
[X]                   25.80
exaOffscreenAlloc     10.78
exaOffscreenFree      8.45

i.e. X is slowing my jobs down by almost half.

I think it's plain where the problem is: the exaOffscreen*() lines are
both new, at least at this position in the profile...