Bad DGA throughput to Matrox Millennium II G200 AGP

Bad DGA throughput to Matrox Millennium II G200 AGP

Post by Ronald Wah » Sun, 13 Jun 1999 04:00:00



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Hi,

Just tested the memory throughput to my Matrox Millennium II G200 AGP with
the dga program that comes with XFree86. It shows very bad ~20 MB/s. After
reading deja(news) I compiled the memset from glibc by myself and got
~28MB/s. But this is not much improvement. So I decided to replace my
Millennium II G200 AGP with an older Millennium II PCI with 4MB WRAM. Now
dga shows a throughput of ~90 MB/s. So there must be something wrong with
my AGP card, The Mainboard-BIOS or XFree86. I hope someone is willing to
help...

--------------------------------
hardware-/configuration details:
--------------------------------

- Board: Asus P5A With BIOS rev. 1007
 (AGP Turbo Mode + AGP posted write are enbled -- playing with them
  didn't help)

- CPU: K6-III/400 (*not* overclocked)

- 160 MB SDRAM (PC-100)

- Matrox Millennium II G200 AGP with 8 MB SDRAM:

 $ cat /proc/pci
 <...>
   Bus  1, device   0, function  0:
     VGA compatible controller: Matrox Matrox G200 AGP (rev 1).
       Medium devsel.  Fast back-to-back capable.  IRQ 15.  Master
         Capable.Latency=64.  Min Gnt=16.Max Lat=32.
       Prefetchable 32 bit memory at 0xe7000000 [0xe7000008].
       Non-prefetchable 32 bit memory at 0xdf800000 [0xdf800000].
       Non-prefetchable 32 bit memory at 0xdf000000 [0xdf000000].

- write combining is enabled for the framebuffer:

  $ cat /proc/mtrr
  reg00: base=0xe7000000 (3696MB), size=   8MB: write-combining, count=1

  disabling it lowers the performance even further

- relevant X output:

  $ Xwrapper

  XFree86 Version 3.3.3.1 / X Window System
  (protocol Version 11, revision 0, vendor release 6300)
  Release Date: January 4 1999
  <...>

  (--) SVGA: Linear framebuffer at 0xE7000000
  (--) SVGA: MMIO registers at 0xDF800000
  (--) SVGA: Video BIOS info block at 0x000c7540
  (--) SVGA: Found and verified enhanced Video BIOS info block
  (--) SVGA: detected an SDRAM card
  (--) SVGA: chipset:  mgag200
  (**) SVGA: videoram: 8192k
  (**) SVGA: Option "dac_8_bit"
  (**) SVGA: Option "power_saver"
  (**) SVGA: Using 16 bpp, Depth 16, Color weight: 565
  (--) SVGA: Maximum allowed dot-clock: 250.000 MHz
  (**) SVGA: Mode "1280x1024": mode clock = 162.000
  (**) SVGA: Mode "768x576": mode clock =  50.000
  (**) SVGA: Mode "320x240": mode clock =  20.000
  (**) SVGA: Mode "352x240": mode clock =  20.000
  (**) SVGA: Mode "352x280": mode clock =  20.000
  (**) SVGA: Mode "352x288": mode clock =  20.000
  (**) SVGA: Mode "384x288": mode clock =  20.000
  (**) SVGA: Virtual resolution set to 1280x1024
  (--) SVGA: SpeedUp code selection modified because virtualX != 1024
  (--) SVGA: Using hardware cursor

- Linux Kernel 2.2.9 with Framebuffer-Console (disabling it didn't make
  any effect)

- glibc 2.0.7pre6  

thx,
ron

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Bad DGA throughput to Matrox Millennium II G200 AGP

Post by Geoff Winan » Thu, 24 Jun 1999 04:00:00


Problem:

If you have a P-2, enable MTRR's in your kernel config, and recompile your
kernel. Also, strip any junk out of it. :)

~Geoff.