3 ms·
Clock speed does not necessarily equal computational speed. I remember how ~15 years ago people predicted that single-core performance was not going to improve
by krylon 9y ago
Clock speed does not necessarily equal computational speed. I remember how ~15 years ago people predicted that single-core performance was not going to improve any longer, and that we would get more and more CPU cores over time.
My first multi-core machine was an Athlon64 X2 with two cores running at 2GHz. Today, my work laptop (ThinkPad L540) has a dual-core CPU (plus 2-way SMT) running at 2.6 GHz (3.2 GHz with TurboBost). But single-core performance has improved notably. Not as much as was common in the 1990s, but still. And for most desktop systems[1] more than two or four cores seem to be pointless, anyway, since they will sit idle most of the time.
[1] I am not talking about developer workstations, CAD machines or other high-end use cases, but the kind of machine where some office drone runs Outlook, Excel, and a web browser.
- beagle3 9y agoMost of this single core improvement, if I understand correctly, comes speculative execution and larger caches (rather than shorter pipelines), which -- in the context of crypto -- means that implementations go to great length to avoid the features that speed up execution, specifically BECAUSE they leak information.
- krylon 9y agoFair point. Now, I know just enough about cryptography to know I know nearly nothing about it, so maybe someone can put this into context: Wouldn't a multi threaded crypto implementation open up a whole bunch of new potential attacks?
- Nexxxeh 9y agoHow many of those cores turbo boost to 3.2GHz though? Isn't it just one, even on the i5-8xxx laptop chips?
- krylon 9y agoProbably. But I rarely push that computer to the point where it uses more than one core, except when I compress large amounts of data.
- ktpsns 9y agoGood argument, but it is probably limited to the x86 architecture (and its contemporary grandchildren). In contrast, the OP explicitely mentions the Raspberry PI with its ARM CPU. This kind of RISC chips (more or less) secretly took over the world since virtually all mobile devices are equipped with such a SoC. It is common knowledge that these CPUs don't deliver the single core power of a desktop CPU but nevertheless parallelize. Without doubt it is worth in getting crypto fast(er) on such devices.
- krylon 9y agoFair point, I had not considered ARM and other low-power CPUs.