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Howto:Use the system monitor: Difference between revisions
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Howto:Use the system monitor (view source)
Revision as of 13:04, 12 February 2012
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Anyway, this alone isn't improving anything yet, but having a GUI to conveniently monitor performance will hopefully help us to see where exactly we're having issues - and help us to improve... | Anyway, this alone isn't improving anything yet, but having a GUI to conveniently monitor performance will hopefully help us to see where exactly we're having issues - and help us to improve... | ||
= Debugging stuttering = | |||
To put it simple, vertex shader performance is affected by the amount of detail visible in the geometry of scene (number of vertices visible), and of course shader complexity itself, while fragment performance is affected by screen resolution(or widow size if you run it windowed) and shader complexity as well. They both affect framerate in the end, since the frame needs to be finished before being put up for display. | |||
Frame delay might be affected by a lot of other stuff, but it's a better measure of smoothness since it displays the "longest" time it had to wait for a frame in a certain amount of time. | |||
There might be some performance lost in high detail scenes, due to the culling (visibility check, and hiding of faces facing away from the camera, or being behind other faces, or too small to display (openscenegraph is smart about that one and it won't "display" faces/parts of objects that would end up too small)) that needs to be done on the scene before it goes through the shaders. | |||
To test if it's a graphics performance issue, you'd do a couple of tests.: | |||
First load up the ufo, oevr detailed scenery, remain static, don't move the view around. Check framerate and frame delay. If they're consistent with each other it might be a graphics performance issue, if not you can be sure there's some other subsystem that does background processing and needs to finish it's stuff. | |||
Move the view around, do you get stutters? If you do, then there's some pressure on your video card's RAM. As it needs to load the new geometry and textures that come into view, it might not have enough space left, so it might need to offload the "old" ones. Even like this framerate should stabilise once you stop moving the view around, or once the rate of movement is slow enough so that the video card can keep up. | |||
Fly straight and level, at reasonable speeds, keeping the view fixed. Do you get stutters? Is framerate consistent with frame delay? If it is, and you get low fps, again it might be a graphics issue, as new random objects come into view and/or the trees shader creates new ones in the distance. If not I's still suspect another susbsytem being the culprit. | |||
You can repeat these with some aircraft, see if and how things change. | |||
In short: if the framerate '''varies along with the Frame Delay''', then it's a graphics performance issue. If framerate is pretty stable, and Frame Delay '''varies more or less wildly''' I'd suspect some other subsystem being the culprit and causing more or less periodic delays as it needs to do it's stuff. | |||