ubuntu-x-swat team mailing list archive

[Aaron Haviland <orion@xxxxxxxxxx>]

Public bug reported:

This describes the problem as seen in
http://www.primegrid.com/forum_thread.php?id=2839
and in
http://forums.nvidia.com/index.php?showtopic=186645

This is not an Ubuntu bug, but an upstream one. I don't believe there is
anything we can do to fix it. Am filing this bug to provide information
and a workaround for people searching for this problem.

This problem has been observed with 260.19.06, 260.19.12, 260.19.21, and
also the beta 260.19.26

Application source is available here:
https://github.com/Ken-g6/PSieve-CUDA

The PrimeGrid application intentionally overloads the CUDA processor
with more threads than it needs (much like people use "make
-j(CPUs+1)"). This seems to expose a bug in the 260 series drivers that
did not exist previously.

This results in the application bailing out with an unpredictable
frequency (on my card, sometimes it would die instantly, others it would
die after a couple minutes. People with different CUDA-capable cards may
find different timings.)

The error reported in the application's stderr.txt is:
| Computation Error: no candidates found for p=1795516820654281
where p=xxxx whatever number was being tested at that point.

Workarounds that are known to work at this point:
1) Downgrade to 256 driver series. (e.g. https://launchpad.net/ubuntu/maverick/amd64/nvidia-current/256.53-0ubuntu3)
2) Use BOINC's app_info.xml mechanism to specify that the program uses fewer threads, with the flag "-m 2"

** Affects: nvidia-graphics-drivers (Ubuntu)
     Importance: Undecided
         Status: New


** Tags: cuda maverick upstream

** Description changed:

  This describes the problem as seen in http://www.primegrid.com/forum_thread.php?id=2839 and in http://forums.nvidia.com/index.php?showtopic=186645
  This is not an Ubuntu bug, but an upstream one. I don't believe there is anything we can do to fix it. Am filing this bug to provide information and a workaround for people searching for this problem.
  
  This problem has been observed with 260.19.06, 260.19.12, 260.19.21, and
  also the beta 260.19.26
  
- Application source is available here: https://github.com/Ken-g6/PSieve-
- CUDA
+ Application source is available here:
+ https://github.com/Ken-g6/PSieve-CUDA
  
  The PrimeGrid application intentionally overloads the CUDA processor
  with more threads than it needs (much like people use "make
  -j(CPUs+1)"). This seems to expose a bug in the 260 series drivers that
  did not exist previously.
  
  This results in the application bailing out with an unpredictable
  frequency (on my card, sometimes it would die instantly, others it would
  die after a couple minutes. People with different CUDA-capable cards may
  find different timings.)
  
  The error reported in the application's stderr.txt is:
  | Computation Error: no candidates found for p=1795516820654281
  where p=xxxx whatever number was being tested at that point.
  
  Workarounds that are known to work at this point:
  1) Downgrade to 256 driver series. (e.g. https://launchpad.net/ubuntu/maverick/amd64/nvidia-current/256.53-0ubuntu3)
  2) Use BOINC's app_info.xml mechanism to specify that the program uses fewer threads, with the flag "-m 2"

** Description changed:

- This describes the problem as seen in http://www.primegrid.com/forum_thread.php?id=2839 and in http://forums.nvidia.com/index.php?showtopic=186645
- This is not an Ubuntu bug, but an upstream one. I don't believe there is anything we can do to fix it. Am filing this bug to provide information and a workaround for people searching for this problem.
+ This describes the problem as seen in
+ http://www.primegrid.com/forum_thread.php?id=2839
+ and in
+ http://forums.nvidia.com/index.php?showtopic=186645
+ 
+ This is not an Ubuntu bug, but an upstream one. I don't believe there is
+ anything we can do to fix it. Am filing this bug to provide information
+ and a workaround for people searching for this problem.
  
  This problem has been observed with 260.19.06, 260.19.12, 260.19.21, and
  also the beta 260.19.26
  
  Application source is available here:
  https://github.com/Ken-g6/PSieve-CUDA
  
  The PrimeGrid application intentionally overloads the CUDA processor
  with more threads than it needs (much like people use "make
  -j(CPUs+1)"). This seems to expose a bug in the 260 series drivers that
  did not exist previously.
  
  This results in the application bailing out with an unpredictable
  frequency (on my card, sometimes it would die instantly, others it would
  die after a couple minutes. People with different CUDA-capable cards may
  find different timings.)
  
  The error reported in the application's stderr.txt is:
  | Computation Error: no candidates found for p=1795516820654281
  where p=xxxx whatever number was being tested at that point.
  
  Workarounds that are known to work at this point:
  1) Downgrade to 256 driver series. (e.g. https://launchpad.net/ubuntu/maverick/amd64/nvidia-current/256.53-0ubuntu3)
  2) Use BOINC's app_info.xml mechanism to specify that the program uses fewer threads, with the flag "-m 2"

-- 
CUDA failures with 260 series drivers
https://bugs.launchpad.net/bugs/683621
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