The cr.yp.to microblog: 2022.06.15 23:06:44

2022.06.15 23:06:44 (1537179825101713408) from Daniel J. Bernstein, replying to "Ruben Kelevra (@RubenKelevra)" (1537014528155783168):

No, I've run various types of heavily optimized code for long periods on all cores on various Intel and AMD boxes _at base frequency_ without coming anywhere close to the thermal limits. Running at higher frequency would mean much more frequent hassle of replacing dead hardware.

2022.06.15 23:20:25 (1537183270663639042) from Daniel J. Bernstein:

CPU manufacturers set the thermal limits on consumer CPUs to avoid obvious short-term failures. They set safer limits and frequencies on the CPUs marketed as server CPUs. It's not a coincidence that server operators frequently publish reports on observed long-term failure rates.

Context

2022.06.15 08:44:22 (1536962803222708224) from Daniel J. Bernstein, replying to "Ruben Kelevra (@RubenKelevra)" (1536957907622928384):

"Obviously"? Have you measured the difference? Would you call it "extreme"? If it turns out that you're waiting primarily for the CPU to finish web-page computations (and not the network), wouldn't the best way to reduce latency be to split those computations across _all_ cores?

2022.06.15 09:38:36 (1536976451731431424) from "Christian Wissel (@Gnarfoz)":

That mixes two audiences unfairly: users, who might decide to go along with your suggestion that variable clock speed is hell and turn it off, and developers, who might be able to re-implement a program to use multi-threading. (developers might be users, but rarely vice-versa)

2022.06.15 09:41:49 (1536977259998879745) from "Christian Wissel (@Gnarfoz)", replying to "Christian Wissel (@Gnarfoz)" (1536976451731431424):

Recommending users turn off turbo boost, and when they inevitably say "but now my $something runs slower!" to reply "well then make it multi-threaded" is hardly a realistic solution. ;-) (Not saying it shouldn't be done, but not by them, most likely.)

2022.06.15 12:09:54 (1537014528155783168) from "Ruben Kelevra (@RubenKelevra)", replying to "Christian Wissel (@Gnarfoz)" (1536977259998879745):

But I mean, there's also "all core turbo boost" and the specified non-turbo boost CPU clock speed is hardly sustainable if there's a 8 thread load for a long time anyway. It will probably be dropped by thermals.