The microblog: 2022.06.15 09:13:44

2022.06.15 09:13:44 (1536970196316876800) from Daniel J. Bernstein, replying to "Gok (@Gok)" (1536963564908515328):

Seems to me that CPUs are generally acquiring more and more cores (even on laptops), and more and more performance-critical code is switching to using those cores, so it's becoming increasingly obsolete to declare that system performance is judged by CPUs running just one thread.


2022.06.15 08:19:36 (1536956569220308992) from Daniel J. Bernstein:

Using all server cores _while keeping the hardware alive for a long time_ is what gets the most computation done per dollar. My experience running >100 servers of many different types is that the best clock frequencies for this are at or below base frequency, no Turbo Boost.

2022.06.15 08:26:46 (1536958374041923589) from Daniel J. Bernstein:

Meanwhile I'm rarely waiting for my laptop, even with it running at very low speed. I'm happy with the laptop staying cool and quiet. Yes, I know there are some people using monster "laptops" where I'd use a server, but are they really getting "extreme" benefits from Turbo Boost?

2022.06.15 08:32:25 (1536959798654009345) from Daniel J. Bernstein:

It's easy to find Intel laptops where the nominal top Turbo Boost frequency is more than twice the base frequency. These laptops can't run at anywhere near that top frequency for optimized computations running on all cores. Where's the "extreme system-wide performance impact"?

2022.06.15 08:47:23 (1536963564908515328) from "Gok (@Gok)":

"Bursty single threaded computations are more than twice as slow" is an extreme system-wide performance impact.