3 ms·

Well, their exposed ISA and ABI are probably considered to be genAsm, which is the aforementioned mostly-LLVM-based IR. The concrete machine code will mostly l

Well, their exposed ISA and ABI are probably considered to be genAsm, which is the aforementioned mostly-LLVM-based IR. The concrete machine code will mostly likely only ever be generated by the specializer in the real world. Consider the specializer to be the static software equivalent of the x86-to-uOp decoding core in the hardware of a modern x86. On the one hand it can only make static scheduling decisions, whereas on the other hand it can look at the entire program being translated to make those decisions rather than just the window of instructions the x86 decoder can see during execution. I really think this is the only path to make a long-term-viable staticly-scheduled architecture. Otherwise you'll wind up with the Itanium problem, which is that you eventually need to rewrite/reorder code internally (in hardware) as your architecture evolves, which kind of removes the advantage of having the static scheduling in the first place.

microcolonel 9y ago
> I really think this is the only path to make a long-term-viable staticly-scheduled architecture. You may be right. I think the challenges involved (especially as OOBC is proposing to solve them) defeat the goal. For systems that have no present or future interest in JIT, it might offer somewhat higher peak performance than whatever commodity computers are on the market; for those with JIT (especially with frequent compilation, like in a web browser) I can see it being prohibitive. I don't care how magical their specializer is, it will cost something to run, and cost a lot to integrate (imagine not being able to know the size or entry point of the basic block until you've specialized it, infuriating!). The way they talk about the specializer, it even gives the impression that they don't intend to share the source code, which will be a whole lot of fun when deciding whether or not you trust it to run in the middle of your application.
- phs2501 9y ago
  Yeah, who knows. I mostly think the Mill is a pile of interesting ideas that just might, if they're very lucky, eventually become a product. I'm certainly not holding my breath though. Regarding their intentions, they've said repeatedly that they want to sell chips. It'd therefore be pretty stupid IMHO to not open up as much as they can the toolchain to get software to run on their chips, including the specializer. For that matter they should definitely also be releasing the chip specification data (insn/op bit patterns, functional unit slot arrangement, latencies, etc) that's used to create the specializer so people can roll their own if they want. Then again this is the same world where Intel ME is an ultra-suspicious closed blob and you can't get datasheets on tons of chips to save your life, which makes no sense to me either. So I'm probably not a very good judge of what's reasonable.

microcolonel 9y ago

> I really think this is the only path to make a long-term-viable staticly-scheduled architecture. You may be right. I think the challenges involved (especially as OOBC is proposing to solve them) defeat the goal. For systems that have no present or future interest in JIT, it might offer somewhat higher peak performance than whatever commodity computers are on the market; for those with JIT (especially with frequent compilation, like in a web browser) I can see it being prohibitive. I don't care how magical their specializer is, it will cost something to run, and cost a lot to integrate (imagine not being able to know the size or entry point of the basic block until you've specialized it, infuriating!). The way they talk about the specializer, it even gives the impression that they don't intend to share the source code, which will be a whole lot of fun when deciding whether or not you trust it to run in the middle of your application.

phs2501 9y ago
Yeah, who knows. I mostly think the Mill is a pile of interesting ideas that just might, if they're very lucky, eventually become a product. I'm certainly not holding my breath though. Regarding their intentions, they've said repeatedly that they want to sell chips. It'd therefore be pretty stupid IMHO to not open up as much as they can the toolchain to get software to run on their chips, including the specializer. For that matter they should definitely also be releasing the chip specification data (insn/op bit patterns, functional unit slot arrangement, latencies, etc) that's used to create the specializer so people can roll their own if they want. Then again this is the same world where Intel ME is an ultra-suspicious closed blob and you can't get datasheets on tons of chips to save your life, which makes no sense to me either. So I'm probably not a very good judge of what's reasonable.