@rygorous@mastodon.gamedev.place
Post #2409993
2025-09-09 01:55 UTC
@regehr@mastodon.social @steve@discuss.systems Also, re: ISA efficiency, I like re-posting this, by now, rather old image that shows you what the score really is.
This was on the Xeon Phis but the general trend holds to this day. (Source: https://people.eecs.berkeley.edu/~ysshao/assets/papers/shao2013-islped.pdf p. 3) NB this is an in-order core with 512b vector units.
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@rygorous@mastodon.gamedev.place 2025-09-09 01:59
@regehr@mastodon.social @steve@discuss.systems This is one of the bigger reasons for why ISA doesn't matter more. Broadly, your uArch is only as good as its data movement, because that shit is what's really expensive, not the logic gates. It's things like: - how good is your entire memory subsystem - how good is your bypass network - how good are your register files etc. It's not like you can't make mistakes in the ISA that will really kill your design, you can. That's what happened to VAX.