David Patterson Says It's Time for New Computer Architectures and Software Languages (ieee.org)

Tekla S. Perry, writing for IEEE Spectrum: David Patterson -- University of California professor, Google engineer, and RISC pioneer -- says there's no better time than now to be a computer architect. That's because Moore's Law really is over, he says : "We are now a factor of 15 behind where we should be if Moore's Law were still operative. We are in the post -- Moore's Law era." This means, Patterson told engineers attending the 2018 @Scale Conference held in San Jose last week, that "we're at the end of the performance scaling that we are used to. When performance doubled every 18 months, people would throw out their desktop computers that were working fine because a friend's new computer was so much faster." But last year, he said, "single program performance only grew 3 percent, so it's doubling every 20 years. If you are just sitting there waiting for chips to get faster, you are going to have to wait a long time."

Comments

Re:so go do it, David

[ranton]

I am pretty sure David Patterson is out there doing it. He is a professor in the field who has accomplished plenty. He is 70 now and is likely past his academic prime, so now he is doing what he should be doing at this time in his career: teaching, mentoring, and inspiring the next generation.

Re:Starting in 2005

[pz]

People confuse Moore's law with performance. Moore observed that the total number of transistors on a chip was doubling every 18 months. For a long time, that meant that the clock frequency was also doubling.

Then, a nasty habit of physics to smack us in the phase --- err, face --- came along in the form of speed of light limitations. Given the size of contemporary chips, it just is not (and is unlikely to ever be, if what we know about fundamental physics is correct) possible to communicate from one side of a 1 cm die to the other much faster than in the range of a handful of gigahertz clock speeds, give-or-take. Even with photons going in straight lines in perfect vacuum (none of which happens on a chip) the best you could hope for would be a 30 GHz clock rate, a paltry ten times faster than today's CPUs.

One obvious solution is to make circuits that are smaller, and thus we started to get more CPUs on a single die. Still, those CPUs need to synchronize with each other, the cache system, etc., so there remain chip-spanning communications constraints.

The limits on the size of transistors, and thus perhaps on the total number on a chip, are looming but haven't arrived yet. The limits of raw clock speed most definitely have. It is safe to say that our chips will continue to get faster for a while, but the heady days of generation-to-generation massive improvements in single-thread CPU performance are over.