hugin-devs team mailing list archive

[Yuv <792896@xxxxxxxxxxxxxxxxxx>]

On August 12, 2011 01:48:57 am Daniel wrote:
> Just wanted to add that setting the CPU affinity worked around the problem
> for me. Hope that helps some people out.

Thank you!  Yes this helps a lot.  It confirms that the issue is one of 
threading, probably expiring cache.  And there are ways for the program itself 
to request affinity.

I suspect that somebody at Apple though about this and affinity is ON by 
default - would explain why Apple is so unaffected.  I did not research links 
to substantiate my hypothesis.  Windows systems tend to have more threads 
running around (antivirus!) which would explain why the cache expires/corrupts 
more often.

On Linux we can use something like
* http://www.ibm.com/developerworks/linux/library/l-affinity/index.html
* http://www.linuxjournal.com/article/6799

And on Windows something like
* http://msdn.microsoft.com/en-us/library/ms686223%28v=vs.85%29.aspx

For the short term:
* Linux http://www.linuxcommand.org/man_pages/taskset1.html
* Windows http://www.addictivetips.com/windows-tips/how-to-set-processor-
affinity-to-an-application-in-windows/

Performance trade-off:
* https://lanvu.wordpress.com/tag/setprocessaffinitymask/

Now it is a matter of time to implement and test...

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https://bugs.launchpad.net/bugs/792896

Title:
  Fast Preview Hangs or Crashes since 2011.0

Status in Hugin - Panorama Tools GUI:
  Confirmed

Bug description:
  EDIT (August 6, 2011): summarized known information

  *WORKAROUND FOR USERS*: disable the Overview

  1- start Hugin
  2- load a project
  3- go to the Fast Preview Window.  don't touch anything else but described below as this could trigger the bug
  4- hit the button Show/Hide to hide the Overview
  5- quit Hugin
  Now Hugin should perform well.

  
  *AFFECTED SYSTEMS*

  - CPU: all systems with more than one thread, that is multi-core CPUs as well as single-core CPUs with hyperthreading.
  - Operating Systems: due to the different implementations of threading and OpenGL on different platform, some systems are more prone to error than others.  Mac OS X seems to be the least affected.  Windows seems to be the most affected.

  
  *AFFECTED VERSIONS*

  - All versions of Hugin since the introduction of the Overview in the Fast Preview are affected.  That is, all versions after revision 4808:8c577b320714 2011-01-09 12:21:18
  - This includes the final releases of 2011.0.0 as well as all beta/candidate releases of 2011.2.0

  
  *SUMMARY FOR DEVELOPERS / BUG HUNTERS*

  This is most likely a threading issue. Lukáš' hypothesis: "a race
  condition in OpenGL calls, when OGL is called by separate threads from
  both overview and fast preview. The reason is that OpenGL is not
  thread-safe and it can cause various problems when used within multi-
  threaded application."

  Run 'valgrind --tool=helgrind hugin' and try to reproduce the error to
  produce a useful backtrace like
  https://bugs.launchpad.net/hugin/+bug/792896/+attachment/2253077/+files
  /valgrind-out.txt

  
  *ORIGINAL BUG REPORT BELOW FOR COMPLETION:*

  Upgraded from 2010.4 to 2011.0.0 and it has hung 3 times in about 15
  sessions.  All three hangs happened while doing the same thing.....
  new session, load images, load a lens profile, set the canvas size
  (Calculate optimal size), save-as and save profile then click on GL
  (fast preview) button.  Fast preview window comes up, shows anchor
  image and then hangs.

  Is not reproducible.  Running 2011.0.0.0fd3e119979c built by Matthew
  Petroff on 64-bit Win7.

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