1/21 - ExtremeTech has run only its second piece on embedded processors in its history that I am aware of. Embedded processors are a topic that it does not normally cover. You have to draw a line somewhere, and I guess ExtremeTech draws it at embedded.

But why the exception this time? Well, the piece covers multicore processors, and it just so happens that multicore has been a part of embedded processors for a long, long time. "Far from being the first multicore CPUs, x86 processors are rather late to the party".

Not that this is a bad thing. It's a good thing. Intel and AMD can benefit from what has gone before. "This intellectual cross-pollination should serve all of us well as we look forward to the new era ofmultiprocessing".

Embedded DSP companies must hate CPU companies. Because the CPU companies keep implementing the functions of embedded DSP chips onto CPUs. That's why so many DSPs become extinct. There's no longer a need for a particular DSP once the CPU carries out its function. The author likens CPUs to black holes, and DSPs to the stars that black holes eat up. Except that in this case, there are more "stars" being born than being gobbled up. In other words, there are more and more DSPs created to carry out new emerging functions. "Entirely new types of processors have been developed to efficiently handle networking data packets, graphics rendering, cryptography, etc. The general-purpose beasts can't keep up".

So here's how multicore comes into the picture with embedded processors. Just as CPUs have become increasingly complex and taken on functions previously handled by DSPs, so many embedded processors became more complex, too, and in so doing became multicore, long before CPUs ever did.

Software largely distinguishes multicore in embedded processors from multicore in x86 CPUs. General purpose CPUs must carry out alot more functions than a specialized DSP. Multicore processors have been around along time. "But the new frontier is making multicore processors work well (efficiently, transparently) in the PC".

CPUs were not the first multicore processors. Embedded processors were. But neither were Intel or AMD the first multicore CPU. That honor goes to IBM, who in the year 2000, introduced the Power4 microprocessor. The Power4 keeps turning up among the analysts featured in the story as the first in some way, shape or form.

There are also hurdles in the near future that multicore CPU makers must mount. One of these still remains heat. Just because the two leading CPU vendors are moving to dual-core does not mean that heat is no longer a problem. Scaling the clock back and putting multiple cores in a package is but a temporary solution at best. "Adding more CPU cores inevitably will make the package run hotter".

The article also talks about multicore as implemented in some of the latest x86 CPUs. The infrastructure for making multicore chips has been present for a long time, even if it hasn't been used until now. Intel's Smithfield and Presler desktop processors implement dual-core in two of the simplest ways possible. Presler puts two processor chips in one package, Smithfield two cores on one die. It was the system bus on single-core desktop processors that made such sleight of hand possible and so quickly.

One of the analysts surveyed defines multicore very broadly as a chip that has two or more separate processing units that operate independently. However, he gives extra points for intelligent sharing between the cores. Examples of this intelligent sharing occur in Intel's new dual-core notebook chip Yonah (Core Duo) and in AMD Hyperthreading technology and on-die memory controller.

Multicore technology for CPUs is pretty much in its infancy. There's a long way to go still, many challenges to meet, and it will be interesting to watch it unfold. "So far, the x86 vendors have made tentative steps by just putting CPUs next to each other with very little interaction. That will change as the designers continue to optimize".