Reconfigurable Systolic Array

I've been searching, and searching, and searching for anything that matches the Bitgrid in architecture... and I've found nothing... today's Google search is reconfigurable systolic array.

I get a lot of results, mostly academic (which means they are behind a paywall, and thus worthless). It does give me a better way to describe the bitgrid, though.

The bitgrid is a fine grained homogeneous 2d reconfigurable systolic array and/or mesh. It will be verified as to utility by simulation. I hope to popularize it with blogs, social media, and making a game out of it.

It is my belief that the flexibility of the LUT based approach more than makes up for the lack of dedicated routing and compute blocks.  Any inactive elements of the circuit are unclocked, and thus should be at very low power.

I'm not sure if I'm going to be a good fit for the OHPC project or not, I've got until August 6 to write a proposal.

Prior art - non found... and I've got a headache

Every single article I checked trying to find a pure LUT based FPGA had some sort of routing fabric in it.

I can't find anything that is close to the bitgrid.

I'm going to try to relax, and wait for the Excedrin to kick in.

Learning about chip design

I really need to find out how much power a BitGrid cell will consume, in order to find out how well it could realistically deliver on the Exascale challenge. This is forcing me to learn all about VLSI design. Thanks to CMOSedu, I'm getting up to speed on Electric and LTspice right now. I hope to learn enough to have an answer within an order of magnitude this week.  I'm hoping I can get it in the range of 1 pJoule/operation/cell for a naive design. This would allow a 1000x1000 chip to operate at 1 watt at 1 Ghz.   I expect static power to be very low.


I've got a month until the first DARPA deadline for submissions...

wish me luck.

What's required for Exascale

I've been watching the google results for the key word "Exascale"... and found this at the bottom of this article about bioinformatics. (Emphasis mine)

And in another opinion piece over at International Science Grid This Week, Irving Wladawsky-Berger, a 37-year IBM veteran, lays out some of the big challenges on the way to achieving exascale computing. Whereas the evolution from terascale to petascale went smoothly using tens to hundreds of thousands of processors from the PC and Unix markets, they will not get us to exascale, writes Wladawsky-Berger. Exascale will require some other kind of major transition in chip architecture, not to mention a completely new programming paradigm. 

Well... that is precisely describes the Bitgrid, or will, once I get the thing built.

SimGrid - Up and running

I managed to get a Grid Simulation working.... here is a screenshot of it. I named it SimGrid, and it works in conjunction with Sim01 as a programming tool. First you work out your entry on Sim01 for a single cell, then paste the hex code into the appropriate cell in the Grid. The code to generate it can scale to arbitrary dimensions, limited by the screen and Windows resource handles.

In this simulation, every cell is loaded with the code required to pass each bit through the cell, and have it emerge on the opposite side. Its a fairly easy way to check for logic flaws in the simulator. Here we see a bit from the left side propagating all the way across to the right.

I feel that it's reasonable to estimate I can emulate an arbitrary grid of these, even as many as 1000x1000 without problem. The problem now is to find a problem domain that is appropriate for the architecture to use as a baseline for performance evaluations. I need to make sure it's going to be quick enough once cast into silicon to have any commercial value. I'm hoping it will be fast enough for the Exaflop realm, but I have to real way to tell at this point in time.

I'm starting to dig around for silicon simulation resources, as well as a place to do fabrication of this as an ASIC should I find funding.

I feel like Tesla probably felt when he got the idea of polyphase power straight in his head.... BitGrid has enormous potential, but now is the time for a lot of blood sweat and tears to make it come into being.