
The dangers of AVX-512 throttling: a 3% impact - zdw
https://lemire.me/blog/2018/08/15/the-dangers-of-avx-512-throttling-a-3-impact/
======
NightMKoder
This might be a bit...too far out there, but could there be side channel
attacks via cpu heating? Like heating the cpu to near borderline with AVX512
and seeing if a hyperthread causes throttling due to some “heavy” aes
instruction. Sounds unlikely to be exploitable though.

Ever since specter I’m thinking of any performance changes by previous
instructions might be exploitable. Again thermal throttling might be a bit too
far out there since it’s not _that_ deterministic. Fun thought though!

~~~
greenpenguin
Not via CPU heating, but a theoretical AVX Spectre attack popped up on HN
recently:
[https://news.ycombinator.com/item?id=17711823](https://news.ycombinator.com/item?id=17711823)

------
JimmyAustin
From my (admittedly little) understanding, part of the concern was that a user
on part of the CPU could degrade performance for other users by sucking up
proportionally more of the heat budget of the entire CPU, triggering
throttling. Is this what was tested here?

