[Intel-gfx] X11 performance regressions

Knut Petersen Knut_Petersen at t-online.de
Wed May 11 23:22:19 CEST 2011


As I do have only a few minutes now, a few comments:

1: The complete trees are compared, all modules/libraries are either old or new. No debug-versions.

2: Speculating about cores is definitely wrong -- the Pentium M Dothan definitely is a single core cpu.

3. There often is a "choked most" (1) -- "choked least" (10) -- "choked a bit more again" (100,500)
     result:

   1450000.0    0.50   1x1 stippled rectangle (8x8 stipple)
    134000.0    1.11   10x10 stippled rectangle (8x8 stipple)
      2540.0    1.05   100x100 stippled rectangle (8x8 stipple)
       110.0    0.95   500x500 stippled rectangle (8x8 stipple)

    Heavy per call impact of factor A on those small requests, light impact of a factor B with growing numbers?
    A = compiler / library overhead?

Yes, there is
>    15400.0    0.54   GetProperty
>    15500.0    0.54   QueryPointer
but we also see
 
     8150000.0    1.21   X protocol NoOperation


4. No, it's not the kernel. I did
    a) boot
    b) x11perf on old X
    c) x11perf on new X
    d) reboot
    e) x11perf on new X
    f) x11perf on old X
    and saw only very marginal differences between those two runs.

5.  Yes,  I do agree to that:
>  I'm actually pretty pleased with the results you've shown, 10%
> or better speedup for basically all text ops, about half of window
> management ops, and almost all window exposure ops. 
6. More later.

cu,
 Knut



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