8 ms·
Superconducting Computer: Imec's plan to shrink datacenters
- justinclift 2y ago> The amount of computing resources used to train the largest AI models has been doubling roughly every 6 months for more than the past decade. Have AI models really been around for a decade?
- elil17 2y agoYes? Much longer than a decade in fact. AlexNet is from 2012, and many would point to that as the end of the AI winter.
- justinclift 2y agoThanks. I guess when people say "AI models" I've been mentally associating that with LLMs which seem like a new thing. :)
- chris_va 2y agoThat's also a fuzzy line :) seq2seq? attention model? BERT model? At least 5 years old, if not 10.
- ted_dunning 2y agoConvectis. From the 90's
- hinkley 2y agoIn 1995 everybody was sure AI would put all developers out of work.
- ordu 2y ago> the system promises to consume only 500 kilowatts of total power. I don't understand, if these 500kW is the power consumed by a computation itself, or does the cooling equipment consumption included? To suck out 500kW of heat out of a shoebox box while keeping box's temperature at 4 kelvin... it seems to me impossible.
- gaze 2y agoA 4 K dry cryostat’s refrigeration system usually eats about 4-5 kW. Not sure what’s going on here.
- karma_pharmer 2y ago4-5kW to extract how many picowatts of heat from the system? You can't quote a number for the cryocooler without knowing how much heat is being injected into the thing it needs to keep below 4.2K.
- boxed 2y agoWell, this isn't just going to keep inert matter cold, this will do massive amounts of computation, so it makes sense that it would need to dump a lot of heat.
- gaze 2y agoSuch 4 K cryostats have about a 30 W cooling power.
- bawolff 2y agoOne presumes a super conducting computer would generate less heat, given the lower resistence due to superconductivity
- IsTom 2y agoCurrent fastest supercomputer has a little over 1 exaflop and consumes over 20MW. 20 exaflops at 500kW is a lot less power, but it'd probably still generate a substantial amount of heat.
- breezeTrowel 2y agoSuperconductors do not generate heat when in their superconducting state. Otherwise they wouldn't be superconductors.
- coreyh14444 2y agoAnyone else find it unnerving that the rendering looks just like the T-800 CPU from Terminator? https://i.ebayimg.com/images/g/19cAAOSwOI9kZH-d/s-l1600.webp https://i.ebayimg.com/images/g/19cAAOSwOI9kZH-d/s-l1600.webp
- boxed 2y agoI wonder what kind of CPU architecture they're targeting, if any. If something like this exists for RISC-V and not ARM or Intel for example, this could have some pretty big effects on the domination of the industry. Or if Intel buys this company and its patents and this is all x86 only...
- zackmorris 2y agoYa that was my first thought too. Since they're targeting AI, they'll probably start with the streaming multiprocessors (SMs) and tensor processing units (TPUs): https://stackoverflow.com/questions/32226993/understanding-streaming-multiprocessors-sm-and-streaming-processors-sp https://stackoverflow.com/questions/32226993/understanding-s... https://primo.ai/index.php?title=Processing_Units_-_CPU,_GPU,_APU,_TPU,_VPU,_FPGA,_QPU https://primo.ai/index.php?title=Processing_Units_-_CPU,_GPU... I take issue with this though because the DSP/SIMD approach that GPUs and TPUs take is a subset of SMP/MIMD (symmetric multiprocessing and multiple instruction multiple data). Where this matters is that today's neural networks are built on matrix operations, which is a narrow niche within computer science. A more general approach which would allow for faster evolution of the 20 or so other algorithms in AI would be to use compute clusters to explore genetic algorithms, simulated annealing and all the rest in playgrounds limited only by the developer's imagination. Loosely that would look like a desktop computer with perhaps 1000 or more cores appearing as a single CPU, that could be programmed in a language of choice like Erlang, Go, Julia, MATLAB, C/C++, etc (optionally using containerization tools like Docker). Or like having something akin to AWS EC2 locally. I believe that this divergence in computing approaches is why Moore's Law ended around 2007 with emphasis switching to low cost and low power mobile and embedded systems. It's also why my heart fell out of programming and I stopped pursuing endlessly more photorealistic game engines that result in everyone making the same game over and over again. If someone out there won the internet lottery and wants to invest in something truly disruptive, some low hanging fruit might be a highly scaled multicore RISC-V processor (as you mentioned) with 100-1000 cores running over 1 GHz using under 100 watts for under $1000. Targeting 10,000 to 100,000 cores by 2030 and 1 million cores shortly thereafter. That's the level of performance we should be expecting from companies like Intel, had Moore's Law continued. And it shows just how far expectations have fallen, with today's personal computers running little faster than those of 2010 for typical (non-GPU) workflows, tragically at the same price of $1000-3000. I also wish that Imec would start with a consumer-level superconducting processor for under $1000, but unfortunately today's socioeconomic reality of widening wealth inequality doesn't support that. But it's easy enough to make liquid nitrogen from the air with a liquid nitrogen generator (looks like they start around $4000, that could/should be disrupted to $400 or less). Unfortunately their Josephson junctions still need liquid helium at 4k it looks like. Probably some company overseas will figure out a 77k liquid nitrogen version and bypass IP law, as these things tend to go lately.
- aconz2 2y agoSounds cool. Does the DRAM exist both in the SPU (4 kelvin) area and 77 kelvin area? This paragraph is a bit confusing: > We call it a superconductor processing unit (SPU), with embedded superconducting SRAM, DRAM memory stacks, and switches, all interconnected on silicon interposer ... Next, there is a glass bridge to a warmer area, a balmy 77 K that hosts the DRAM. Having 20 exaflops in a 20x20x12 cm volume is cool, but aren't you going to need a memory bandwidth close (factor 10 - 1000 lets say depending on arithmetic intensity) to that to be useful? And total memory capacity as well. I feel like the bytes/second/area (bandwidth flux) would be the limiting factor to make use of that compute density From the linked paper https://pubs.aip.org/aip/apl/article-abstract/122/18/182604/2888573/Superconducting-pulse-conserving-logic-and?redirectedFrom=fulltext https://pubs.aip.org/aip/apl/article-abstract/122/18/182604/... the projected JSRAM density is 4MB/cm2 so barely anything on the SRAM front
- luyu_wu 2y agoInteresting how they use inductors for memory? My conventional thinking would imply that when you put a few billion of these together on a single package it's bound to create interference. Amazing to read through this though, as someone who's studied mostly traditional computer architecture this stuff is absolutely boggling.
- amelius 2y agoI just got comfortable about the idea of having magnets near my computer, and now this.
- marcosdumay 2y agoYes, the interference is the point. Spintronics does calculation in the interference.
- mpreda 2y agoI would like to see more research into superconducting applied to computing, vs. the "quantum computing" applied to computing. I feel that while superconductibility is actual and proven technology that just waits to be applied to a new field (computing), QC is a "dream about the future". OTOH I think there are theoretical lower bounds on the amount of energy that needs to be ejected as heat from a non-reversible computation, such that a non-reversible SC would still need to produce some heat.
- grondilu 2y ago> OTOH I think there are theoretical lower bounds on the amount of energy that needs to be ejected as heat from a non-reversible computation, such that a non-reversible SC would still need to produce some heat. Yes, it's called Landauer's principle, but it's so low it can be ignored for most intent and purposes.
- karma_pharmer 2y agoIn grad school I extrapolated the charts showing joules per bit of computation, looked at where it intersected the landauer limit compared to my own lifespan, and immediately lost interest in adiabatic computation. No regrets yet.
- grahamrow 2y agoCertain flavors of superconducting digital logic (there are a handful) such as AQFP (adiabatic quantum flux parametron) actually get close to the Landauer limit (with cooling power excepted). Interconnect (as some comments have noted) and lack of a good memory technology are the challenges for all these architectures.
- raziel2701 2y agoTechnical challenges I'd like to see more discussion on from IMEC: - Superconductors are lossy with AC signals, is this loss not a big problem? - Cooling things is very expensive, is this approach not simply transferring the costs to the cooling plant? - I imagine that having a superconducting interconnect represents an impedance discontinuity, effects like the large kinetic inductances in superconducting materials have large ramifications on signal integrity. Any comments on how to deal with these problems? I worry when I see the words "top-down approach" towards this problem because from my experience it should be driven bottom-up. Superconducting circuits are not just: 'Oh it's lossless in DC, everything is great!' You have new limitations on trace dimensions because if you go too small or you drive too large a current you kill the superconducting state. - NbTiN with amorphous Si as the barrier. How sensitive is the system to stray magnetic fields and stray radiation? If one of these structures switches into the normal state can it reset itself like sc photon detectors do or are the phonons trapped and the structure is latched in the normal state? It's nice to see people working on this.
- tonetegeatinst 2y agoI'm just here to remind everyone of the helium shortage.
- ta988 2y agoThere are a lot of ways to do helium recycling (common these days for MRI magnets), never 100% but close. Also there is a lot of helium wasted because it is not worth saving for the small amounts you could sell.
- karma_pharmer 2y ago- Superconductors are lossy with AC signals, is this loss not a big problem? In this logic style, data are represented with fluxons. One fluxon is the quantum unit of flux. You can't have "half a fluxon" in a superconducting loop. In that sense it's actually "more digital than" anything in commercial CMOS chips. The circuit can still malfunction of course -- the failure mode looks like a fluxon failing to move from one logic stage to the next. The real worry is that cryocooler though. Cryocoolers that can do liquid helium temperatures have efficiency ratings around 1%, so that 500kW shoebox is going to need an entire cooling tower attached to its refrigerator.
- datadrivenangel 2y agoYears ago I met a guy at a dinner party who had done some work for DARPA around super conducting computers. The big appeal was energy efficiency and speed: 100s of GHz and ~99% energy reduction. One critical limitation is that information transfer from superconducting to regular wiring is relatively energy intensive, so a superconducting CPU won't actually result in advantages for input/output intensive processing. For processing heavy jobs though, if you don't have to shuffle data around the speed and energy savings will be very attractive.
- Szpadel 2y agoAFAIK current CPUs power usage for calculations is in pJ ( pico joule ) and that's why we are doing speculative execution because that's almost free the issue is that moving that data even to anything outside the core is cost about 100x that so the main every consumption for CPU is not in doing actual computation but in moving data around
- grishka 2y agoIsn't speculative execution there to do something potentially useful during clock cycles that would've been otherwise wasted?
- dgacmu 2y agoIt's mostly about avoiding the latency penalty. There's only so much ILP you can extract from the instruction stream before you get stuck waiting for a dependency. If you started executing that dependency speculatively, it will complete earlier, so you can launch the next instructions sooner. That lets you speed up single-threaded execution more by adding more functional units (since you can't really jam the clock speed any more).
- vasco 2y agoThis is exactly it. Speculative execution comes from instruction set design and basic constraints of branching. The energy consumption could make speculative execution prohibitive, but it's not "the" reason we do it.
- krunck 2y ago"Scientists have predicted that by 2040, almost 50 percent of the world’s electric power will be used in computing. What’s more, this projection was made before the sudden explosion of generative AI. The amount of computing resources used to train the largest AI models has been doubling roughly every 6 months for more than the past decade. At this rate, by 2030 training a single artificial-intelligence model would take one hundred times as much computing resources as the combined annual resources of the current top ten supercomputers. Simply put, computing will require colossal amounts of power, soon exceeding what our planet can provide. " So is Bitcoin still "evil"?