3 Replies Latest reply on Jun 29, 2008 6:19 PM by rafal.lewczuk@gmail.com

    Ubuntu 8.04/amd64 instability

    rafal.lewczuk@gmail.com
      Where can I submit bug reports ?

      Hi,

      I'm not sure it is <<Stream>> question  but as the problem does appear only when trying amdbrook demos, I'm posting it here. Also, question to QA folks: there are so many people running Ubuntu on this forum, would you like to add ubuntu box to your testing fleet ?

      I've bought a HD3870 (not X2) card to learn something about GPGPU and got into problems right after installing it. Finally  I've got amdbrook/amdcal demos working after a bunch of workarounds but some are still crashing my system. floyd_warshall_d for example. Graphics itself seems to work well albeit I didn't test it extensively. Help. Details below:

      My machine: Q6600+8GB RAM, PCI remap option turned on (not tested turning it off though - but I'll do it ASAP and post results). Gigabyte HD 3870 card.

       

      Workaround 1: changed MTRR settings due to fglrx crashing my system right after starting X (problem with fglrx appearing machines with >= 3GB RAM):

      # cat /proc/mtrr

      reg00: base=0x00000000 (   0MB), size=2048MB: write-back, count=1
      reg01: base=0x80000000 (2048MB), size=1024MB: write-back, count=1
      reg02: base=0xc0000000 (3072MB), size= 256MB: write-back, count=1
      reg03: base=0x100000000 (4096MB), size=4096MB: write-back, count=1
      reg04: base=0x200000000 (8192MB), size= 512MB: write-back, count=1
      reg05: base=0x220000000 (8704MB), size= 256MB: write-back, count=1

      Note that I've left a hole between 3328MB and 4096MB. I'm not sure what shall I put here. write-combining ? nocache ?

      Workaround 2:  # export LIBXCB_ALLOW_SLOPPY_LOCK=true

      Workaround 3: removed splash from kernel boot parameters - to prevent switch from X to text crashing my machine;

      Workaround 4: agp=off boot parameter (but I'm not sure it is needed anymore - it worked with my previous mobo where issue with PCI memory remapping caused panic during boot).

       

      Regards,

      rle

       

        • Ubuntu 8.04/amd64 instability
          michael.chu
          Hi rle,

          Let me see if I can get Ubuntu testing and support added seeing as there are enough people using Ubuntu.

          Michael.
            • Ubuntu 8.04/amd64 instability
              rafal.lewczuk@gmail.com

              Hi,

              More details.

              1. Turning off [PCI remap] feature does not make things better nor worse (except for enforcing change of MTRR settings accordingly);

              2. Removinng agp=off does not change anything.

              3. List of demos crashing my system: domain, double_precision_simple_matmult_d, image_filter_d, indexof, indexof_d, mandelbrot, prefix_sum, simple_matmult.

              Please note that double_precision_optimized_matmult_d works correctly while double_precision_simple_matmult_d crashes.

              4. Demos on list always crash my system, demos not on this list do not. I've not tested it very extensively, however - repeated few picked crashing programs (just to see yet another freeze) and run one or two non-crashing programs in a loop (plus repeated few other randomly picked to see them working again).

              One more suggestion: adding a 64-bit box with >4GB RAM would be also nice - as RAM is so cheap today - I suppose 8GB will not be so uncommon among number crunching folks.