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Nvidia Physics Engine Almost Complete
Nvidia has stated that their translation of Ageia's physics engine to CUDA is almost complete. To showcase the capabilities of the new tech Nvidia ran a particle demonstration similar to Intel's Nehalem demo, at ten times the speed. "While Intel's Nehalem demo had 50,000-60,000 particles and ran at 15-20 fps (without a GPU), the particle demo on a GeForce 9800 card resulted in 300 fps. In the very likely event that Nvidia's next-gen parts (G100: GT100/200) will double their shader units, this number could top 600 fps, meaning that Nehalem at 2.53 GHz is lagging 20-40x behind 2006/2007/2008 high-end GPU hardware. However, you can't ignore the fact that Nehalem in fact can run physics."
Is a particle motion simulator a abnormally easy test case?
When I was getting up to speed on IBM Cell programming, IBM had a programmer's tutorial (excellently written, btw). The example problem they used for their chapter(s?) on code tuning were a particle simulator. It was a wonderful example problem, because it showed how to vectorize a program. But then when we went to vectorize our own algorithm, it didn't fit the Cell's vector programming instructions nearly as cleanly, so in the end we didn't get nearly the performance increase due to vector instructions as did the particle simulator.
So I'm thinking that just even though CUDA can do a good job with particle motion simulations, we shouldn't remotely assume that it's good for particular algorithms for which each of us is responsible.
http://www.nvidia.com/object/cuda_get.html offers: "NVIDIA Driver for Linux with CUDA Support (169.09)"
So, physics should work on Linux, having been ported to CUDA already, and CUDA being cross-platform, but the question is if any Linux games will actually support and/or make use of it.
Particle systems are about as perfectly a parallel problem as it's possible to get- and not only that, the calculations are generally very straightforward with few (if any) general CPU control structures (branches, loops, etc).
As a result, the massively parallel hardware on a GPU that exists to render many triangles/pixels/shader programs/etc at once can be exploited to calculate updates for many particles at once. The CPU is at an inherent disadvantage because it is only leveraging a small subset of it's full capabilities.
The CPU is very good at *lots* of different tasks. The GPU is phenomenally good at a very specific set of tasks. Physics just happens to fit within that set.
The ringing of the division bell has begun... -PF
In its most basic definition, a GPU is just a CPU that's been highly specialized towards graphics. It can't do anything that a CPU can't also do, it just is able to do particular things much faster. Basically, they take a lot of the common tasks that graphics require of a processor, and they put really efficient ways to do it directly into the hardware, and they put a whole lot of them.
Think of a CPU as a big tool box. There's something in there for every task, including a screwdriver that can be used to put screws into things. Then next to it, you have a big cordless 18 volt drill (The GPU). Way easier to drive screws with that than the manual screwdriver in your toolbox. But when you need to drive a nail instead, yeah you could bash it in with your screw gun, but it's easier to go back to your toolbox and find a hammer.
I guess that would make a physics processor the nail gun. Or something...
One time I threw a brick at a duck.
Huh? The local physics computations are only being used for presentation and local extrapolation. The server recomputes the relevant physics anyway, and can re-sync everyone periodically. That's how FPSes work to reduce lag--they do local extrapolation, and the server periodically snaps everyone back in line. It sometimes leads to what John Carmack calls "paradoxes" where locally displayed events get undone, but it works.
So, if some portion of your local physics calculation is purely for local presentation (e.g. game outcome doesn't depend on exactly how dirt particles fly around or boobs bounce, but you want it to look realistic), the server doesn't need to reproduce any of that to model the game correctly. Your screen might look different than someone else's, but in an immaterial way. For the super-soaker example, the server will still compute actual "wetness," possibly with a simplified model that skips computing the goosebumps and most of the dripping water.
--JoeProgram Intellivision!
id seem to make all their games for Linux, and they also like using random accessories like that USB flak jacket thing that simulates you getting shot (by quickly puffing up pockets of air with pneumatic compressors). No doubt Quake 5 or whatever will support it at least.
which is totally what she said