Single-chip processors have reached their limits
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Single-chip processors have reached their limits
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Re: Single-chip processors have reached their limits
#2"More multi-chip processor designs" != "single-chip processors have reached their limits".
Re: Single-chip processors have reached their limits
#3Are we moving this way because bigger chips with many cores have worse yields? so the answer is to make lots of little chips and fuse then together?
Re: Single-chip processors have reached their limits
#4It's surprising it took that many cores before the limit was reached!
Re: Single-chip processors have reached their limits
#5Are we moving this way because bigger chips with many cores have worse yields? so the answer is to make lots of little chips and fuse then together?
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Re: Single-chip processors have reached their limits
#6The best chiplet interconnect may turn out to be no interconnect at all. Wafer scale integration [1] has come up periodically over the years. In short, just make a physically larger integrated circuit, potentially as large as the entire wafer -- like a foot across. As I understand it, there's no particular technical hurdle, and indeed the progress with self-healing and self-testing designs with redundancy to improve yield for small processors, also makes really large designs more feasible than in the past. The economics never worked out in the favour of this approach before, but now we're at the scaling limit maybe that will change.
At least one company is pursuing this at the very high end. The Cerebras WFE-2 [2] ("wafer scale engine") has 2.6 trillion transistors with 800,000 cores and 48 gigabytes of RAM, on a single, giant, integrated circuit (shown in the linked article). I'm just an interested follower of the field, no expert, so what do I know. But I think that we may see a shift in that direction eventually. Everything on-die with a really big die. System on a chip, but for the high end, not just tiny microcontrollers.
[1] https://en.wikipedia.org/wiki/Wafer-scale_integration
[2] https://www.zdnet.com/article/cerebras-continues-absolute-do...
Re: Single-chip processors have reached their limits
#7"Reached their limits" - I feel like I've heard this many many times before.
Not that I doubt it, but just I've also been impressed with the ingenuity that folks come up with in this space.
Re: Single-chip processors have reached their limits
#8The best chiplet interconnect may turn out to be no interconnect at all. Wafer scale integration [1] has come up periodically over the years. In short, just make a physically larger integrated circuit, potentially as large as the entire wafer -- like a foot across. As I understand it, there's no particular technical hurdle, and indeed the progress with self-healing and self-testing designs with redundancy to improve…
There are some new chip manufacturing technique coming down the pipeline, which will lead to prices dropping and likely "wafer-scale" will get to the mainstream.
Re: Single-chip processors have reached their limits
#9Are we moving this way because bigger chips with many cores have worse yields? so the answer is to make lots of little chips and fuse then together?
Yeah, in the very general case, chip errors are a function of die area. Cutting a die into four pieces so that when an error occurs in manufacturing, you only throw out a quarter of the die area is becoming the right model for a lot of designs.
Like all things chips, it's way more complicated than that, fractally, as you start digging in. Like AMD started down this road initially because of their contractual agreements with GloFlo to keep shipping with GloFlo does, but wanted the bulk of the logic on a smaller node than GloFo could provide, hence the IO die and compute chiplets model that still exists in Zen. It's still a good idea for other reasons but they lucked out a bit by being forced in that direction before other major fabless companies.
This is also not a new idea, but sort of ebbs and flows with the economics of the chip market. See the VAX 9000 multi chip modules for an 80s take on the same ideas and economic pressures.
Re: Single-chip processors have reached their limits
#10> UCIe is a start, but the standard’s future remains to be seen. “The founding members of initial UCIe promoters represent an impressive list of contributors across a broad range of technology design and manufacturing areas, including the HPC ecosystem,” said Nossokoff, “but a number of major organizations have not as yet joined, including Apple, AWS, Broadcom, IBM, NVIDIA, other silicon foundries, and memory vendors.”
The fact that the standard doesn’t include anyone who is actually building chips makes me very pessimistic about it.