[osg-users] OSG thread profiling results are in!!

James Killian James_Killian at hotmail.com
Wed Jul 2 23:28:46 PDT 2008


"
We are using some particle effects pretty heavily, and we noticed (using filemon) that the smoke image file is being read over and over again, many times (perhaps once per frame).  Is this possible?  We are going to look into that next.  Maybe we can cache the single image (state set)?
"

I found a way to cache the images.  The Registry in osgDB has the ability to set options.  It appears that _options is NULL by default, the options have a CACHE_IMAGES flag to use along with others.  This works against any code that uses readImage(filename).  There are others to explore too:

Does anyone have any experience with using these options?  is there any others that should or should not be used? 



James Killian
  ----- Original Message ----- 
  From: rpingry at gmail.com 
  To: OpenSceneGraph Users 
  Sent: Wednesday, July 02, 2008 2:11 PM
  Subject: Re: [osg-users] OSG thread profiling results are in!!


  Hi Robert,

  I got the stats handler working on our scene and displaying.  I am not sure I understand what the different numbers mean and how I might work with them.  I can see the optimization effort is a big deal.  I know it is beyond the scope of this group.  Are there any resources out there to look at?  

  I have finished the work you had already mentioned, like using png rather than bmp everywhere.  We are also working on making sure our images are as small as possible.  We are also going to work on using LOD.  Since we are in space and most ships are far away, we are sure we can make a big jump there.  I used osgUtil::Optimizer and that game me a few more frames.

  What are some other suggestions?

  We are using some particle effects pretty heavily, and we noticed (using filemon) that the smoke image file is being read over and over again, many times (perhaps once per frame).  Is this possible?  We are going to look into that next.  Maybe we can cache the single image (state set)?

  Thanks
  -- Rick


  On Sat, Jun 28, 2008 at 11:55 AM, Robert Osfield <robert.osfield at gmail.com> wrote:

    On Sat, Jun 28, 2008 at 4:35 PM, James Killian

    <James_Killian at hotmail.com> wrote:

    > The thread profiler does provide detailed information of every threaded
    > activity at any given time.  I just wish there was some way to present the
    > information given that would be more meaningful to the group.
    >
    > What would be great is to have a big balanced scene that can put OSG Viewer
    > to the test in a way where it puts equal intense stress on update, culling,
    > and draw dispatch.  What I'd hope to see is the draw dispatch be on a
    > separate thread, where that thread showed mostly I/O activity, and the cpu
    > activity on other threads.


    The osgViewer::StatsHandler will display update, event, cull, draw
    dispatch on all systems and draw GPU stats.  The GPU stats require an
    OpenGL extension that I've only seen Nvidia implement so far, so you
    won't see this stats printed out on all systems.

    Also record a camera path/game sequence that you can use for
    benchmarking so that every run the app does the same thing, then
    you'll be able to study the effects that changes you make have on
    final performance.  You'll also be able to study the above stats to
    where the problems occur in your scene.

    As a small note, the OSG in CullDrawThreadPerContext,
    DrawThreadPerContext and CullThreadPerCameraDrawThreadPerContext run
    graphics in a separate thread.

    Robert.

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  -- 
  >> Rick
  Check us out at http://fringe-online.com/ 


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