3 ms·
Note that I actually think Itanium is somewhat architecturally interesting and that VLIW is both simultaneously over and under estimated/appreciated. I wanted t
by deepnotderp 9y ago
Note that I actually think Itanium is somewhat architecturally interesting and that VLIW is both simultaneously over and under estimated/appreciated. I wanted to just highlight the example of a chip that definitely shook the world, and it didn't even have to succeed to do it!
Regarding the Mill: I still haven't heard a (good) answer for the perennial question: Where's the ILP?
Every time I ask this question, I'm pointed to the "phasing" talk. The issue is:
1) It's quite similar to a skewed pipeline (which Denver already has) in which you "statically schedule across branches" and delay the start until it's inputs are ready. Now, Denver did quite well indeed, but it's hardly a replacement for OoO.
2) Even from the examples that they show, it's clear that this is no where near 3x the ILP, at best, even from their own example, it provides 2x.
I hope the Mill can do well in embedded because they have quite a few good ideas (albeit many of which have already been done which they claim is their own, such as XOR-ing addresses, done by Samhita), and because the computer architecture industry is currently starved for innovation.
- marcosdumay 9y agoILP == instruction level parallelism? If so, it's on pseudo-vectorial instructions made by concatenating many opcodes on the same instruction word. I don't think they claim it performs better than OoO, just that it uses less power.
- deepnotderp 9y agoYes. What? What do you mean by pseudo-vectorial instructions? Do you mean loop auto vectorization?
- marcosdumay 9y agoNah, it's late here, and I'm already saying stupid things. I was talking about the mechanism that gives parallelism to the CPU, while you are talking about intrinsic level of parallelism on the programs. Just dismiss it. I was even going to delete it, but I took too long.
- deepnotderp 9y agoAh, no worries, I kind of suspected you were talking about VLIW ;)