I've come across some API calls that involves profiling, but that seems a little bit too much work. Maybe they have a deal with Intel so they can sell more of their VTune, who knows?!

And yeah, the NVidia docs ARE good!

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Found this on a web site: "Although Visual C++ does not ship with a profiler", so I guess profiling stops with VC++ 6.0 . At least easy profiling...

Also, it seems like it's just the .NET Framework that has the profiling API calls when I read on.

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I found a free profiler to use with VS.NET. Haven't tried it, but if someone is interesed, the link is:

http://www.compuware.com/products/devpartner/profiler/default.asp

[edited by - ALiENiD on August 19, 2003 9:01:48 AM]

iNsAn1tY, using the profiler will show where a bottleneck occurs within the code. This assumes that the main bottleneck of the program is in the CPU, i.e. your fps are limited by the number of calculations the CPU is having to perform for each frame (e.g. AI, collision detection, occlusion culling etc.).

If the bottleneck is in the GPU (e.g. fill-rate limits as I mentioned in my previous post) the CPU is basically waiting around for the gfx card to finish drawing the scene, and the profiler cannot help you (since making any CPU routines run faster will not help your fps - the CPU will still be waiting for the graphics card to catch up).

I believe the depth-buffer can help in fill-rate limited scenarios: While the vertex data still has to be sent to the gfx card, the depth buffer will prevent hidden surfaces from being rendered, since they are behind other polys. This means the texturing and lighting operations (and maybe others?) will not need to be performed for the hidden polys and so the frame rate will increase. Hence if decreasing the window size increases the frame rate, the bottleneck was the fill-rate limitations of the gfx card (fps increases because there are fewer pixels to "fill"), it cannot be the cpu since the same number of calculations are still being performed by the CPU (sending vertices etc.)

Are the only two types of bottleneck therefore fill-rate limited and CPU limited then? Or have I forgotten others? I guess vsync could be seen as a bottleneck in that it is a fps limiter!

iNsAn1tY, your post on the profiler was very useful, I had heard of it but never got round to using it. I guess it would be used to locate the source of a CPU bottleneck more precisely, but won''t tell you if your bottleneck is fill-rate or GPU limited, AFAIK.

A program can be fill bound or transform bound. There was a nice two part article on it in Game Developer magazine recently(june and july) by Guillaume Provost. Hopefully it''ll appear on Gamasutra soon.

Look at superpig''s engine tutorial, it has info about how to create a profiler; allowing you to see which parts take up the most time

Oli

All the best problems start with C

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