What’s That Echo?

Multicore chips are one piece of the solution to creating chips at advanced process nodes, but they aren’t the whole solution.

Don’t take my word for it. The powers that be—very large chip makers with big development budgets—are fretting over the future of multicore programming. The question being whispered is, ‘If it doesn’t work, what then?’

That’s a many-billion-dollar ‘if,’ and the answer to that question will almost certainly be painful to some engineers. But to date, the number of productivity and corporate-specific applications that truly benefit from having more than one core rather than a faster single core is slim, and the number that can take advantage of four cores is even slimmer. From there the number falls off a sheer cliff, with databases and search applications being the biggest exceptions.

To make up for that programming limitation, some very smart people are thinking about how to rearrange things inside the box. Multicore provided a one or two node bridge, but unless something miraculous happens—and many people are pessimistic about that after four decades—the next big steps forward will be based on materials science.

We’ve been hearing for several years that bulk CMOS is running out of steam. At the front end of the Moore’s Law road map, strained silicon has provided a bridge to yet another node. SOI will likely add a couple more bridges, after which the FinFET model—a new Field Effect Transistor structure with fins—will take over, based on an SOI substrate.

FinFETs and Intel’s Tri-gate model do roughly the same thing. Both use vertically stacked gates, which allow more space for electrons to move. Gates All Around FETs surround the channel with gates, offering yet another approach. All of these solutions reduce current leakage, which means even lower power and less heat. Because heat was the reason behind the addition of so many cores in the first place, don’t be surprised if someone starts cranking up the clock speeds again for a standard number of cores.

It’s important to note, however, that there is no shame in limiting the number of cores on a chip. It’s always good to experiment with new technologies. Failure often forces innovation and leads to the development of new ideas. Looking back over the past four decades of chip development, most of the advancements in chip design were made one painful node at a time. Remember the 1 micron wall?