The cr.yp.to microblog: 2022.06.15 09:06:35

2022.06.15 09:06:35 (1536968395890970625) from Daniel J. Bernstein, replying to "Robert Merget (@ic0nz1)" (1536964541505994752):

The claim at issue of an "an extreme system-wide performance impact" is from outside researchers, not from Intel and AMD. Of course CPU manufacturers collect detailed performance evaluations regarding hundreds of ideas to see which ones will save percentages here and there.

Context

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 08:38:21 (1536961290656047104) from Daniel J. Bernstein:

What I find particularly concerning about these unquantified claims of an "extreme" impact is that, in context, these claims are trying to stop people from considering a straightforward solution to a security problem. If the costs are supposedly unacceptable, let's hear numbers.

2022.06.15 08:51:16 (1536964541505994752) from "Robert Merget (@ic0nz1)":

I would expect that Intel and AMD already have those numbers?