Monthly Archives: March 2015

Stop Everything, We’re Doing 8-LUTs

[With apologies/thanks to The Onion]

Commentary • Opinion • business • ISSUE 15•03 • March 6, 2015
By Josh Gane, CEO and President, XilTera

Would someone tell me how this happened? We were the vanguard of programmable logic. The XilTera StraTex was the cool device to design in. Then the other guy came out with a 6-LUT FPGA. Were we scared? Hell, no. Because we hit back with a little thing called the CLM. That’s a 6-LUT with a dual ported synchronous LUT RAM. For register files and so much more. But you know what happened next? Shut up, I’m telling you what happened—the bastards went to superfracturable LUTs. Now we’re standing around looking foolish selling plain 6-LUTs and a LUT RAM. RAM or not, suddenly we’re the chumps. Well, screw it. We’re going to 8-LUTs.

Sure, we could go to 7-LUTs next, like the competition. That seems like the logical thing to do. After all, 6-LUTs worked out pretty well, and seven is the next number after six. So let’s play it safe. Let’s make a 7-input 6,6-LUT and call it the UltraLUT. Why innovate when we can follow? Oh, I know why: Because we’re a business, that’s why!

You think it’s crazy? It is crazy. But I don’t give a damn. From now on, we’re the ones who have the edge in the LUT inputs game. Are they the best programmable logic a designer can get? Hell, no. XilTera is the most programmable programmable logic around.

What part of this don’t you understand? If 4-LUTs are good, and 6-LUTs are better, obviously 8-LUTs would make us the best freaking FPGA that ever existed. Comprende? We didn’t claw our way to the top of the FPGA game by clinging to the 4-LUT industry standard. We got here by taking chances. Well, 8-LUTs are the biggest chance of all.

Here’s the report from Engineering. I don’t want to hear those three damnable letters V.P.R. ever again! They don’t tell me what to invent—I tell them. And I’m telling them to stick two more LUT inputs in there. I don’t care how. Make the mux tree FinFETs so thin they’re invisible. Put some LUT configuration cells in the CLM cluster switchbox. Partially populate it. I don’t care if they have to cram the seventh and eighth input in perpendicular to the other six, just do it!

You’re taking the “balanced” part of “balanced architecture” too literally, grandma. Cut the strings and soar. Let’s hit it. Let’s roll. This is our chance to make programmable logic history. Let’s dream big. All you have to do is say that 8-LUTs can happen, and it will happen. If you aren’t on board, then screw you. And if you’re on the board, then screw you and your father. Hey, if I’m the only one who’ll take risks, I’m sure as hell happy to hog all the glory when the 8-LUT FPGA becomes the device for the U.S. of “this is how we reconfigurably compute now” A.

People said we couldn’t go to 6-LUTs. It’ll blow up the size of the input muxes and configuration bitstream, the LUT mux tree wiring will be too long, they said. Well, we did it. Now some egghead in a lab is screaming “8-LUTs are crazy?” Well, perhaps he’d be more comfortable in the labs at Lactel, working on antifuse crossbars. ONO, my ass!

Maybe I’m wrong. Maybe we should just ride in AltLinx’s wake and make voltage regulators. Ha! Not on your damn life! The day I shadow a penny-ante outfit like AltLinx is the day I leave the FPGA game for good, and that won’t happen until the day I die! The market? Listen, we make the market. All we have to do is put her out there with a little jingle. It’s as easy as, “Hey, technology mapping complex datapaths with anything less than 8-input LUTs is like playing pushing-on-a-rope whack-a-mole with some bad-approximation-timing-model physical synthesis CAD.” Or “There’ll be so few logic levels between the hard logic blocks, I could put Intel out of business.”

I know what you’re thinking now: What’ll people say? Mew mew mew. Oh, no, what will people say?! Grow up. When you’re on top, people talk. That’s the price you pay for being on top. Which XilTera is, always has been, and forever shall be, Amen, 8-LUTs, sweet Jesus in heaven.

Wait. I just had a stroke of genius. Are you ready? Open your mouth, baby birds, cause Mama’s about to drop you one sweet, fat nightcrawler. Here she comes: Put another carry chain on that sucker, too. And hell, why stop there? Two write ports. That’s right. 8-LUTs, fracturable into four 6-LUTs, four clock enables on the flops, two carry chains, 256b LUT RAM, and two write ports. You heard me—two write ports. It’s a whole new way to think about memory bandwidth intensive massively parallel accelerators. Don’t question it. Don’t say a word. Just key the music, and call the chorus girls, because we’re on the edge—the rising clock edge—and I feel like dancing.