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Five Nvidia CUDA-Enabled Apps Tested
crazipper writes "Much fuss has been made about Nvidia's CUDA technology and its general-purpose computing potential. Now, in 2009, a steady stream of launches from third-party software developers sees CUDA gaining traction at the mainstream. Tom's Hardware takes five of the most interesting desktop apps with CUDA support and compares the speed-up yielded by a pair of mainstream GPUs versus a CPU-only. Not surprisingly, depending on the workload you throw at your GPU, you'll see results ranging from average to downright impressive."
CUDA is a framework that will work on Windows and Linux.
I know you are trolling, but actually CUDA applications work better on Linux than on Windows. If you run a CUDA kernel on Windows that lasts longer than 5~6 seconds, your system will hang. The same will happen on Linux but then you can just disable the X server or have one card providing your graphical display and another one as your parallel co-processor.
Waste your GPU cycles on something more interesting than SETI...
http://www.gpugrid.net/
http://distributed.net/download/prerelease.php (ok, maybe that's less interesting...)
And why limit this discussion to CUDA? ATI/AMD's STREAM is usable as well...
http://folding.stanford.edu/English/FAQ-ATI
h.264 encoding didn't improve with more shaders for some of the results(like PowerDirector 7), because of the law of diminishing returns.
I remember reading about x264 when quad-cores were becoming common. It mentioned that if quality is of the utmost importance, you should still encode on a single core. It splits squares of pixels between the cores; where those squares connect there can be very minor artifacts. It smooths these artifacts out with a small amount of extra data and post processing; the end result is a file hardly 1-2% bigger than if encoded on a single core, but encoded roughly 4x faster.
Now, if we're talking about 32 cores, or 64, or 128, would the size difference be bigger than 1-2%? Probably. After a certain point, it would almost certainly not be worth it.
This is supported by Badaboom's results, where the higher resolution videos (with more encoded squares) seem to make use of more shaders when encoding, while most of the lower resolution vids do not. (indicating that some shaders may be lying idle)
What I'm curious about, is could the 9800GTX encode two videos at once, while the 9600GT could only manage one? ;)
I'm also curious why the 320x240 video encoded so quickly - but that could be from superior memory bandwidth, shader clockspeed, and some other important factor in h.264 encoding.
Take it with a grain of salt; I'm not an encoder engineer; just regurgitating what I once read, hopefully accurately. ;)
Folding@Home runs its computations in short bursts. gustgr is talking about a single computation kernel that takes more than 5-6 seconds.
I hear this a lot in CUDA/GPGPU-related threads on slashdot, primarily from people who simply have zero experience with GPU programming. The bottom line is that in the present and for the foreseeable future, if you are going to try to accelerate a program by offloading some of the computation to a GPU, you are going to be tying yourself to one vendor (or writing different versions for multiple vendors) anyways. You simply cannot get anything approaching worthwhile performance from a GPU kernel without having a good understanding of the hardware you are writing for. nVidia has a paper that illustrates this excellently, in which they start off with a seemingly good "generic" parallel reduction code and go through a series of 7 or 8 optimizations -- most of them based on knowledge of the hardware -- and improve its performance by more than a factor of 30 versus the generic implementation.
Another thing to keep in mind is that CUDA is very simple to learn as an API -- if you're familiar with C you can pick up CUDA in an afternoon easily. The difficulty, as I said in the previous paragraph, is optimization; and optimizations that work well for a particular GPU in CUDA will (or at least should) work well for the same GPU in OpenCL.
But OpenCL is a specification, not an implementation. The only 3 implementations I'm currently aware of is Apple's (with Snow Leopard), AMD demoed implementation back in March, and Nvidia's beta implementation. So far none of those are open source. If you're aware of an open source implementation, please let me know I'm actually very interested in it, but have yet to locate one.
OpenCL is an Open Standard compute language which comprises:
If you're writing an OpenCL-aware device device driver for a GPU, you'll probably need to wait a bit for some open source examples. It's reasonably likely that there will be some included in Darwin (once updated for Snow Leopard).
Look to the LLVM project (sponsored heavily by Apple and others) for an open source compiler which will (if it doesn't already) know about OpenCL.
It sounds like you might be looking for a higher level API which allows you to more easily use the OpenCL, or possibly for language bindings to Java or Python perhaps? I suspect you'll see those coming along, once Apple ships Snow Leopard, and people have a chance to kick the tires, and then integrate LLMV into their tool chains, extend various higher level API, bridge to Java and whatnot.
The earliest high level API to take easy and broad advantage of OpenCL will probably be from Apple, of course. They'll likely provide some nicely automatic ways to take advantage of OpenCL without programming the OpenCL C API directly. As a Cocoa programmer, you'll be using various high level objects, maybe an indexer for example, which have been taught new OpenCL tricks. You'll just recompile your program and it will tap the GPU as appropriate and if available. The Cocoa implementation is closed source, but people will see what's possible and emulate it in various open source libraries, on other platforms, for Java and other languages.
Here's a good place to start: OpenCL - Parallel Computing on the GPU and CPU. Follow up with a google search.
If you mod me down, I shall become more powerful than you could possibly imagine.
Uhh...Cray is still very much alive. And doing vectors. And threads. And multicore. All long before Intel/AMD.
Seymour Cray was killed by a speeding redneck in a trans-am in 1996.
The company currently known as Cray as formerly known as TERA, which bought the assets of Cray Research from SGI who acquired Cray Research after Seymour had left to form Cray Computer which is also defunct.
Seymour was never significantly involved in multi-core or multi-threaded processors or NUMA. In fact, he specifically avoided designs even hinting of that sort of complexity because he felt that simplicity in design made it easier to fully utilize the maximum performance of the hardware.
When information is power, privacy is freedom.