[osg-users] how to interpret values shown by stats handler

[Werner Modenbach]

OK, thanks Robert.

So I do a couple of frames until values stabilize. The shown average is
what I finally need.

- Werner -

Am 17.07.2018 um 12:12 schrieb Robert Osfield:
> Hi Werner,
>
> The values are averaged as otherwise they'd jump around so much that
> they would be un-readable blur.
>
> The exact values are all collated in the the various osg::Stats
> objects, so perhaps you can have a look at these.
>
> As a general note, OpenGL timing data is not deterministic, this is
> partly down to the OpenGL FIFO blocking at different points in the
> frame, or sometimes the OS and the driver interacting in different
> ways each frame.  This effect gets worse the more overloaded your
> system is.
>
> This means you need to take the stats as hint to what is going on, but
> it's not hard fast, to really understand you need to be aware of how
> various things interact.
>
> Robert.
>
> Robert.
> On Tue, 17 Jul 2018 at 10:43, Werner Modenbach
> <Werner.Modenbach at texion.eu> wrote:
>> Hi all,
>>
>> I'm trying to optimize the display speed of my application by testing
>> various techniques.
>>
>> In order to do exact measures I implemented a mechanism where I can
>> trigger single frame() calls from my keyboard.
>>
>> Curiously the GPU times shown by the stats handler are always drifting
>> somehow over significant ranges
>> before getting stable. Does anybody know if there is some averaging over
>> a couple of frames or is there any other effect
>> I don't see at the moment? Or is this a kind of caching effect?
>>
>> It's difficult to judge the effects of techniques under those
>> circumstances if I don't have an idea what is causing the drifts.
>>
>> Thanks for any hints.
>>
>> - Werner -
>>
>>
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