Shiftings in Architectures

Cell, the hype

Sony is working on a new kind of processor which they call Cell. A single Cell processor is said to have a 1/75th of the power of the Blue Gene/L supercomputer in teraflops, and that for 400 dollars.

The new Cell processor is hyped, a lot. People are shouting that the performance of the PlayStation 3, which will feature a Cell processor, will blow away those of the competers: the XBox and the Revolution, both using claimed to be slow PowerPC processors.


So what are these Teraflops? Why aren’t they talking about Hertzes anymore?

A TeraFLOPS stands for 1,000,000,000,000 Floating point Operations Per Second. (TeraFLOPS on wikipedia).

A normal computer has a few GigaFLOPS (one TeraFLOPS is 1000 GigaFLOPS).

The Cell processor in the PS3 will have 1,8 TeraFLOPS. It is very easy to believe that the PS3 will inheritly be about 500 times faster than a normal computer. But that is false.

The performance of a computer isn’t all about how fast a computer can calculate with floating point numbers. The performance of a computer has got to do with a lot more than that. Simply doubling the memory performance (not specificly memory bandwidth, but the whole) would have a bigger impact than doubling the amount of TeraFLOPS, even on applications that heavily rely on floating point operations.

So why have a lot of TeraFLOPS then? It is quite simple, the new platforms haven’t got seperate GPU’s (Graphical Processing Units), their task is now intergrated into the CPU. And what was their task? Calculating, a lot, with floating points.
The amount of TeraFLOPS on the new platforms are the sum of the amount of TeraFLOPS of both the GPU and the CPU. A GPU needs to calculate a lot with numbers for 3d rendering.

Your normal computer has got a lot more than those few GigaFLOPS in your CPU in your GPU already. Although the leap to over the one TeraFLOPS is certainly impressive.


Super Computers need to do a lot of FLOPS too, they calculate models which got a lot of floating points. So why put the Cell processor in the Ps3 instead of directly in some supercomputer? Simple, marketing. Almost everyone that is superficially following the computer news is telling me over and over again that the Cell processor is the most incredible thing there is. It is hyped.

Linux on Ps3

Also the Cell processor uses a whole new architecture which still has to be tested a lot to mature. Sony will let you install Linux on your Ps3? Why? Simple, because they want the Linux community to add decent support for the Cell architecture.

New Architectures & CLI

I guess it will be a matter of time before new architectures will come. A problem with a lot new architectures is that there isn’t a lot of support for them yet. The solution? CLI’s like Java and .Net could bring the solution.

Microsoft rumoured to have MSIL running (semi)natively on their XBox360 and making Longhorn more and more rely on .Net (the ontop applications, not the kernel offcourse) means a lot less architecture dependency.

I wonder what will happen, but one thing is sure.. things are shifting.

XBox 360

Microsoft released the specifications of the XBox 360..
it is a beast..

With 3 CPU cores running on 3.2Ghz each with 2 hardware threads and 1 mb l2-cache each it is a powerhouse.

A remarkable feature of the XBox 360 is that it has got processor level support for MSIL (the bytecode used by .net applications).

The best thing of the XBox 360 is that it’ll be quite cheap (~150$), this probably lets the XBox360 deliver the most processor capability per dollar.

Maybe I’ll buy a few and make my own little linux server cluster with it, when the guys behind have added support for the XBox360 :-).