2 ms·

>maybe NAND gates are not the ideal fundamental building block here? It's my long held opinion that LUTs (Look Up Tables) are the basis of computation for the

>maybe NAND gates are not the ideal fundamental building block here? It's my long held opinion that LUTs (Look Up Tables) are the basis of computation for the future. I've been pondering this for a long time since George Gilder told us that wasting transistors was the winning strategy. What could be more wasteful than just making a huge grid of LUTs that all interconnect, with NO routing hardware? As time goes by, the idea seems to have more and more merit. Imagine a grid of 4x4 bit look up tables, each connected to its neighbors, and clocked in 2 phases, to prevent race conditions. You eliminate the high speed long lines across chips that cause so much grief (except the clock signals, and bits to load the tables, which don't happen often). What you lose in performance (in terms of latency), you make up for with the homogenous architecture that is easy to think about, can route around bad cells, and be compiled to almost instantly, thanks to the lack of special cases. You also don't ever have to worry about latency, it's constant.

phdelightful 3y ago
It’s been a long time since I worked on FPGAs, but it sounds like FPGAs! What do you see as the main differences?
- mikewarot 3y ago
  No routing, no fast lines that cut across the chip, which cut way down on latency, but make FPGAs harder to build, and especially hard to compile to once you want to use them. All that routing hardware, and the special function units featured in many FPGAs are something you have to optimize the usage of, and route to. You end up with using solvers, simulated annealing, etc... instead of a straight compile to binary expressions, and mapping to the grid. Latency minimization is the key to getting a design to run fast in an FPGA. In a BitGrid, you know the clock speed, you know the latency by just counting the steps in the graph. BitGrid performance is determined by how many answers/second you can get from a given chip. If you had a 1 Ghz rack of BitGrid chips that could run GPT-4, with a latency of 1 mSec per token, you'd think that was horrible, but you could run a million such streams in parallel.

phdelightful 3y ago

It’s been a long time since I worked on FPGAs, but it sounds like FPGAs! What do you see as the main differences?

mikewarot 3y ago
No routing, no fast lines that cut across the chip, which cut way down on latency, but make FPGAs harder to build, and especially hard to compile to once you want to use them. All that routing hardware, and the special function units featured in many FPGAs are something you have to optimize the usage of, and route to. You end up with using solvers, simulated annealing, etc... instead of a straight compile to binary expressions, and mapping to the grid. Latency minimization is the key to getting a design to run fast in an FPGA. In a BitGrid, you know the clock speed, you know the latency by just counting the steps in the graph. BitGrid performance is determined by how many answers/second you can get from a given chip. If you had a 1 Ghz rack of BitGrid chips that could run GPT-4, with a latency of 1 mSec per token, you'd think that was horrible, but you could run a million such streams in parallel.