[osg-users] Slow down with shared nodes

Tue Mar 7 23:40:39 PST 2017

Hi Robert,

attached you will find two screenshots while running in
SingleThreaded-Mode. Using osgUtil::Optimizer does not make any big
difference. I will try to create an example, so that you can test it on
your computer.

André

2017-03-07 18:10 GMT+01:00 Robert Osfield <robert.osfield at gmail.com>:

> Hi André,
>
> Thanks for the screenshots.  They tells us it's the draw dispatch that
> is gating performance, so the question now moves to why draw dispatch
> is so slow in this case.
>
> Are you running the osgUtil::Optimizer on your scene graph?
>
> Could you run the tests with SingleThreaded threading model?
>
> There may be chance that a bug fix to the OSG somewhere has tightened
> up the assumptions it makes about threading.  That's just a guess
> though, there still is too few titbits of information to know what the
> cause is.
>
> Robert.
>
>
>
> On 7 March 2017 at 16:40, Andre Normann <andre.normann at gmail.com> wrote:
> > Hi Robert,
> >
> > some more screenshots. This time without any other model.
> >
> > 3.2.3_1: My application using 3.2.3 and sharing nodes
> > 3.4.0_1: My application using 3.4.0 and sharing nodes
> > 3.4.0_2: My application using 3.4.0 without sharing nodes
> >
> > Best regards,
> > André
> >
> >
> > 2017-03-07 17:27 GMT+01:00 Andre Normann <andre.normann at gmail.com>:
> >>
> >> Hi Robert,
> >>
> >> I attached two screenshots. As you can see, I am doing nothing fancy
> here.
> >> There is a VirtualPlanetBuilder model present in the scene, but this
> model
> >> is hidden for my test case. The test scene contains only some thousand
> >> triangles and I am using a GeForce 1080 which can handle much more.
> >> Currently I have no idea what is going wrong here.
> >>
> >> -André
> >>
> >>
> >> 2017-03-07 11:33 GMT+01:00 Robert Osfield <robert.osfield at gmail.com>:
> >>>
> >>> Hi André,
> >>>
> >>> I can't think of any changes between 3.2.x and 3.4.0 that would cause
> >>> a slow down like you are describing.
> >>>
> >>> The best way to start looking at what might be the cause would be to
> >>> isolate what part of the application is the bottleneck, the first step
> >>> would be to use on the on screen stats and then look at the costs of
> >>> the update, event, cull, draw dispatch and draw GPU phases.
> >>>
> >>> Also have a look at the full stats with to see if there is a different
> >>> number of nodes or state being rendered in the two cases.
> >>>
> >>> Robert.
> >>>
> >>>
> >>>
> >>> On 7 March 2017 at 08:21, Andre Normann <andre.normann at gmail.com>
> wrote:
> >>> > Hi,
> >>> >
> >>> > I am currently migrating from OpenSceneGraph 3.2.3 to 3.4.0. In my
> >>> > application I get a significant slow down, when I share nodes. Here
> is
> >>> > a
> >>> > quick example layout of my scenegraph:
> >>> >
> >>> >
> >>> > Parent
> >>> >   |
> >>> >   + ---> MatrixTransform1 --> Node1
> >>> >   |
> >>> >   + ---> MatrixTransform2 --> Node1
> >>> >   |
> >>> >   ...
> >>> >   |
> >>> >   + ---> MatrixTransform3 --> Node1
> >>> >
> >>> > I have a root node with several MatrixTransforms. The nodes below the
> >>> > MatrixTransforms are shared. In 3.2.3 everything works well and I
> have
> >>> > a
> >>> > framerate of 60 Hz. In 3.4.0 the framerate drops with each new added
> >>> > MatrixTransform. But when I do not share the nodes and instead create
> >>> > clones
> >>> > with a DEEP_COPY_ALL flag, everything is well in 3.4.0.
> >>> >
> >>> > So what could cause the slow down in 3.4.0 with node sharing?
> >>> >
> >>> > I am using OpenSceneGraph 3.2.3/3.4.0 with a release build on Window
> 7.
> >>> >
> >>> >
> >>> > Best regards,
> >>> > André
> >>> >
> >>> >
> >>> > _______________________________________________
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> >>> >
> >>> > http://lists.openscenegraph.org/listinfo.cgi/osg-users-
> openscenegraph.org
> >>> >
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> >>
> >>
> >
> >
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