4 ms·

Yeah that's the theory, but reality is different and probably why we don't see any in production. (The last company that would admit to a tiny bit of clockless

Yeah that's the theory, but reality is different and probably why we don't see any in production. (The last company that would admit to a tiny bit of clockless logic, Wave, folded). The reality is that doing clockless logic introduces a lot of overhead at every state, both area and timing. There is different styles and the issue are different for them, but the bottom line is that nobody has been able to realize the theoretically wins in production (note1). And that's not even addressing the lack of tooling. note1: the closet IMO is Ivan Sutherlands group which have some very impressive claims, but still nothing you can run out and buy.

blagie 5y ago
I don't think that's right. 1) I think an architecture change -- any architecture change -- is expensive. Intel and AMD dumped many billions of dollars into R&D around existing architectures, and an asynchronous one starts without a lot of that benefit. 2) There's a ton of stuff -- chipsets, RAM, software, etc. -- built up around synchronous. The engineering cost go up astronomically. 3) That's not to mention baseline engineering costs. Async won't give a 2x boost to performance. I would guess it'd be 10%, maybe even 30%. That's not nearly enough to justify the investment. Ivan Sutherlands' work certainly won't compete with teams 10+x times that size and investment.
- FullyFunctional 5y ago
  There is no 10% boost - it's fiction ADDED: With the millions spent on getting just a minor single digit improvement, you think the big players wouldn't jump on clock-less immediately if they could? Note, Intel did use (does?) use domino logic in the ALU and FPU. The benefit just isn't there for clock-less. I personally know of companies that tried and gave up on it. To your other points, you wouldn't boil the ocean; you keep everything else clocked as usual and bridge between them.
  - blagie 5y ago
    I think there's a long graveyard of conceptually better architectures which died because people underestimated costs, from Transmeta, to all sorts of SIMD and MIMD systems, to VLIW. I agree it's not too expensive to prototype, but it's super-expensive to do *right*.

blagie 5y ago

I don't think that's right. 1) I think an architecture change -- any architecture change -- is expensive. Intel and AMD dumped many billions of dollars into R&D around existing architectures, and an asynchronous one starts without a lot of that benefit. 2) There's a ton of stuff -- chipsets, RAM, software, etc. -- built up around synchronous. The engineering cost go up astronomically. 3) That's not to mention baseline engineering costs. Async won't give a 2x boost to performance. I would guess it'd be 10%, maybe even 30%. That's not nearly enough to justify the investment. Ivan Sutherlands' work certainly won't compete with teams 10+x times that size and investment.

FullyFunctional 5y ago
There is no 10% boost - it's fiction ADDED: With the millions spent on getting just a minor single digit improvement, you think the big players wouldn't jump on clock-less immediately if they could? Note, Intel did use (does?) use domino logic in the ALU and FPU. The benefit just isn't there for clock-less. I personally know of companies that tried and gave up on it. To your other points, you wouldn't boil the ocean; you keep everything else clocked as usual and bridge between them.
- blagie 5y ago
  I think there's a long graveyard of conceptually better architectures which died because people underestimated costs, from Transmeta, to all sorts of SIMD and MIMD systems, to VLIW. I agree it's not too expensive to prototype, but it's super-expensive to do *right*.