PS3 Folding@Home Begins with Impressive Numbers

hansamurai writes "As we've previously discussed, the Folding@Home client is now available on the PS3, and already some early results are in. The total number of teraflops generated by PS3s has already exceeded all other OS contributions combined and the entire project is heading towards one petaflop of distributed computing power. Stanford notes that their teraflops calculation is conservatively calculated so the total power could be under-appreciated. With the PS3 European release complete and the Folding client already available to them, the number of users will continue to grow for the time being, let's hope that the project does not run out of work units to pass out. Kotaku has some numbers that are a few hours old since the Stanford server is getting hit pretty hard with the renewed interest in the project."

Comments

impressive

[mastershake_phd]

Impressive, but I wonder if this interest among PS3 owners will drop off. Especially when GTA IV comes out, or they get next months power bill.

For 64bit floats, the PS3 is a powerhouse

[maynard]

Cell is very optimized toward one data type for calculation: 64bit floats. If you want to efficiently use the PS3 in a cluster, just be aware that your code must:

a) use primarily 64bit floating point

b) either:
            - fit code and data segments within 256K for each SPU
            - crunch long enough between streamed data blocks such that DMA latency doesn't kill performance

c) have the entire calculation broken down into no more than six parts for streaming (one per SPU)

There are SPU userspace threading models that run cooperatively (similar to the old userspace pthreads, I guess), but the thread manager consumes valuable SPU RAM. Also, SPUs don't support a supervisor bit for memory protection... so... bad things happen when threaded code running on SPU goes tits up.

If you want to calculate 128bit floats, ints, or have lots of branch logic... buy a quad core2duo; cell don't do you any good.

BTW: Anyone here hacking GEANT or BLAST for Cell?

Re:For 64bit floats, the PS3 is a powerhouse

[maynard]

I was already corrected on the issue of floats. I appear to have been misinformed. However, on many of these issues you appear to be splitting hairs. For example, you appear to argue that an SPU does not lack a supervisor bit - but instead go on a tangent about how SPUs don't have local memory access, but must instead perform a DMA transfer. Well, as it turns out, the SPU does NOT have a supervisor bit for memory protection.

Your other arguments boil down to: we don't program Cell like that. In particular, you're discussing how to double buffer and/or stream many code/data segments on Cell with low performance penalty. I'm sure you're right for your particular task (which I assume is game programming). However, that is not the best choice for coding up a Monte Carlo sim. Particularly since it might actually be possible to cram the algorithm and data segment straight into LS. And regarding your userspace threading argument: when a simulation that just spent CPU days (or weeks) in compute goes tits up, bad things do happen. Heh.

power bill

[DogDude]

Somehow, I doubt that people buying a $600 game system will care if their power bill goes up $1 (or $10 or $20) a month. Power is one of those things that most people ignore and simply pay unless it's completely out of whack. My commercial power bill fluctuates by sometimes as much as a hundred bucks a month, but even that's not enough to make it worth my time to figure out what might be causing it.

Re:What's so impressive here...

[ucblockhead]

The combination of the numbers and the power. Folding@home just tripled its power. If you think Folding@Home is important, that's important.

If, on the other hand, you're only worried about arguments about what machine is "better", then yeah, you're right.

But not everything in life is about CPU dick-waving contests.

Re:What's so impressive here...

[MarcoAtWork]

I like that folding got a significant speedup, don't misunderstand me, I just don't particularly care for the fanboyism that's happening with people going on on how much more powerful the PS3 is than a PC and yadda yadda yadda. I really appreciate that the PS3 crowd is contributing so much, although I think this might die off a bit when the novelty factor won't be there anymore.

Although the folding folks were smart to put on an animated 3d screensaver with the client which will make it that much more likely that folks will keep this running, I wonder about burn-in of the white-on-dark text line statistics that I've seen on the various videos: I wonder if those could be disabled (or if they orbit around the screen).

Re:What about global warming?

[ScrewMaster]

True ... but "better" is relative for the supercomputer owner. Anyone with a conventional supercomputer pays for the power himself. In the PS3 Folding@Home project, not only the processing is highly distributed: the electric bill is as well.