alt Hacker NewsI miss itanium. I feel like a madman for saying it, but I do. Something about it is just alluring to me. Alas, the problems were too hard to solve or weren't worth solving anymore
Ironically, it died around the time LLMs/AI started becoming good. I feel like the compiler problems with vliw could be solved to a degree with a purpose built ai
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People have tried all kinds of techniques for VLIW, including techniques that are much better than a purpose built AI, AI isn't a magic silver bullet. Fundamentally there's no reason you can't analyse a piece of code to death, and maximally extract parallelism out of it
The fundamental issue is that there simply doesn't exist enough information to be able to extract the necessary parallelism without a rewrite, its the same issue as trying to autovectorise. You can do it to some degree, but it doesn't work in practice to be able to fill out a very wide architecture with reasonable efficacy
The SIMT programming model has proven to be much more successful vs trying to autovectorise or mash things into a VLIW architecture
I think it died before that, it was just that buried it then.
It was neat to live through the era where CPUs constantly got faster and they were willing to try such oddball stuff.
For such a long time it became “faster and more cores, don’t be different” and just didn’t seem as interesting.
Apple Silicon had been very interesting to me. I’m really hoping to see a stronger ARM push on Windows, both because I know it can be great and because it’s just interesting. Windows has never had to switch architectures (for consumers) or support two at once for any reasonable population.
Also, whatever happened to mill? We used to get posts about them all the time.
And I wonder what would have happened to Power if they had the 3rd party fabs that exist today instead of being stuck with what IBM could make in-house.
Itanium was effectively dead once Intel adopted AMD's x86-64. It just remained a zombie for another 15+ years.
Even if the magical Itanium compiler did exist, Itanium would have still lost to AMD64. As soon as you introduce anything that doesn't behave in a statically predictable manner (multitasking, or virtualization, or even an application that processes unpredictable input like a web backend or database), your performance drops down to a fraction of what a similarly priced AMD64 chip could do. VLIW is great for some very specific workloads like HPC, but Intel should have never tried to replace x86 with it.
> Ironically, it died around the time LLMs/AI started becoming good.
What?
I think maybe you are confusing Itanium with something else?
Development on itanium stopped in 2013:
> On 31 January 2013 Intel issued an update to their plans for Kittson: it would have the same LGA1248 socket and 32 nm process as Poulson, thus effectively halting any further development of Itanium processors.[1]
It's true that it shipped until 2021, but I think you had to already have previous orders to get that.
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So I feel like I need to write a blog post about this, but succinctly I think there's a good argument to be made that the issue wasn't the compiler despite popular wisdom. I don't even think it was the nature of unpredictable memory access times either as the itanium has a ton of special architectural hardware to handle unpredictable memory accesses (a lot of which are essentially some of the primitives that an OoO core uses for internal bookkeeping, just exposed architecturally).
I just think the arch has a similarity to archs like cell where it was planned for a world without the end of dennard scaling and just stopped making sense when we weren't targeting scaling to 10Ghz consumer CPUs and beyond.
The relatively fixed clock period that makes sense post ~2006 also means that the CPU architecture of that made the most sense ~2006 (Tomasulo OoO cores) continues to make sense, with most of the process gains going to just making bigger, wider cores.