Prospects For the CELL Microprocessor Beyond Games

News for nerds writes "The ISSCC 2005, the "Chip Olympics", is over and David T. Wang at Real World Technologies put a very objective review of the CELL processor (the slides for the briefing are also available), covering all the aspects disclosed at the conference. Besides the much touted 256 GFlops single-precision floating point performance the CELL processor has 25-30 GFlops in double-precision, which is useful enough for scientific computation. Linus seems interested in CELL, too."

Comments

Re:x86 compatibility?

[Decaff]

What good is a new chip, no matter how fast it is, if you can't run anything on it?

There is this really neat group of operating systems called Unix/Linuxes. They have a major advantage in that you only need a small amount of assembler to get going on a new chip, then the rest can be ported over in C/C++. This has been the situation for decades - Unix (and now Linux) has been the initial OS for almost all new chips.

How fast will this chip be at general purpose stuff? Who cares if it can do 100GFLOPS on a couple operations.

Reasonable point, but FLOPs are a good general measure of the speed, as they are pretty complex operations. We all used to measure speed in MIPS (Million Instructions Per Second), but as chips got so diverse, one chip's instruction could not be easily compared with another's (particularly if RISC chips were involved, where the instructions could be very minimal). FLOPs are a better measure, as a divide is a divide and a multiply is a multiply no matter what chip architecture you use.

Re:Deja Vu

[nutshell42]

He wrote that the platform may "signal the company's intention to move upscale from current game consoles, cutting a wider swath through the living room," with its abilities to function like a stand-alone DVD player and Internet set-top box.

Well one reason the PS2 sold like hot cakes was that it was one of the cheapest DVD players at that time (at least in Japan). There is media player software available and it's quite popular the reason it isn't a internet set-top box is that noone wants internet set-top boxes they died a painful death. Now there's no EE desktop PC because it's too slow but the difference between Cell and PS2 in this regard are

(a) Cell was co-designed by IBM which has an interest in selling workstations etc with that chip, Sony didn't it's not their business
(b) Cell is designed for multiprocessor environments so if it becomes too slow for a task you can simply throw more processors at it
(c) 2000 the clockspeeds still doubled every 18 months that stopped. x86 goes the way of multiple cores too so the programmers will have to get used to parallel design anyway

That doesn't mean it will replace x86 or even make a dent but it means that contrary to the EE it's designed for such stuff and one of the companies behind it sells specialized workstations so it's at least a possibility.

And this time you can find more credible sources than CNET (CNET's part of the yellow press of computer news sites. Almost as bad as yahoo news) who'll tell you that.

Re:What's the point?

[dfj225]

It seems like Cell will have more memory bandwidth than the processors commonly used today. From this article:

" The memory and processor bus interfaces designed by Rambus account for 90% of the Cell processor signal pins, providing an unprecedented aggregate processor I/O bandwidth of approximately 100 gigabytes-per-second. "

Re:More Cell reviews?

[adam31]

Well you can't say it isn't news for nerds. And this article has enough added information in it that I thought it to be worth posting. Most Cell news stories are dumbed down for the nonnerds, whose most pressing question is "Does it run Windows?" This article is the best source I've seen of all the info we know about Cell, without a painful amount of editorializing.

It seemed there was a lot of misinformation/confusion going around because some people heard it supported DP floats and some people heard it used Altivec (which doesn't support DP). So half the people extrapolated that IBM had ditched Altivec (i.e. VMX), and the other half assumed there was no DP support... both of which angered people. The truth (according to this article) is that it uses BOTH: A version of VMX that supports DP. whew!

The article also points out that the SP floats aren't truly 754-compliant, as they round-toward-zero on cast to int. This makes it compatible with that horrible C/C++ truncation cast (If anyone knows why C opts to round-toward-zero, please let me know!). However, rest assured, DPs are 854-compliant.

Also, the article suggests that there is a memory limit (at least initially) of 256MB:

The maximum of 4 DRAM devices means that the CELL processor is limited to 256 MB of memory, given that the highest capacity XDR DRAM device is currently 512 Mbits. Fortunately, XDR DRAM devices could in theory be reconfigured in such a way so that more than 36 XDR devices can be connected to the same 36 bit wide channel and provide 1 bit wide data bus each to the 36 bit wide point-to-point interconnect. In such a configuration, a two channel XDR memory can support upwards of 16 GB of ECC protected memory with 256 Mbit DRAM devices or 32 GB of ECC protected memory with 512 Mbit DRAM devices.

To the putz who submitted this news post:

[Hannibal_Ars]

If you're going to rip the links out of one of my Ars news posts and submit them to slashdot (in the same order in which I linked them, no less), then at least credit your source.