touch-packages team mailing list archive

[Colin Ian King <1466273@xxxxxxxxxxxxxxxxxx>]

It may be that the process is swapped out, so the delivery of the
SIGKILL takes a while for it to be swapped back in and to hence get the
signal.

To test this hypothesis:

a)  one could disable swap and see if the process can be delivered  the
SIGKILL and how quickly it responds to that.  However, turning swap off
may cause the OOM killer to change the way things behave and hence is
not a viable test pattern.

b) run smemstat (from ppa:colin-king/white)  and see how much memory of
the given blocked process is swapped out compared to the memory
resident.  If it is mostly swapped out, it could indicate why it is
taken a while to get swapped back in and to respond to the SIGKILL.

c) one could add a mlockall() to the slow responding process  or even
mlock() on the range of text pages that handle the signal and do the
ppoll so it's not swapped out. Note that one needs to allow the process
to have the CAP_IPC_LOCK capability or one could tweak the
RLIMIT_MEMLOCK soft limit using ulimit -l

-- 
You received this bug notification because you are a member of Ubuntu
Touch seeded packages, which is subscribed to gstreamer1.0 in Ubuntu.
https://bugs.launchpad.net/bugs/1466273

Title:
  gstreamer fails intermittently

Status in Thumbnail generator for all kinds of files:
  New
Status in gstreamer1.0 package in Ubuntu:
  New

Bug description:
  gstreamer occasionally fails to extract a thumbnail from a video file.
  It's clearly a race condition because, almost all of the time, it
  succeeds. To reproduce:

  Check out the thumbnailer/devel branch at r217 and build it. Then:

  cd build/src/vs-thumb

  ./vs-thumb fd://0 ./x.jpg <../../../tests/media/testvideo.ogg

  Point a browser at the generated x.jpg file and check that the image
  was extracted correctly.

  Now run

  while ./vs-thumb fd://0 ./x.jpg <../../../tests/media/testvideo.ogg ;
  do :; done

  Within maybe a hundred iterations or so, I get:

  Error creating thumbnail: ThumbnailExtractor: change_state(): reading
  async messages: GStreamer error: negotiation problem.

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