[_delirium]

One problem is that the article seems to incorrectly assume that "theory" always ignores memory hierarchies. That was true in, say, 1975, but the past 20 years of algorithms theory pays a lot of attention to memory hierarchies. You can even get all sorts of off-the-shelf algorithms designed to perform well on typical modern memory configurations.

I mean, he's basically arguing that CS hasn't revisited heaps since 1961, and hasn't noticed that things like caches or VM pressure might change what the optimal algorithm looks like. But that's of course not the case.

[jemfinch]

> I mean, he's basically arguing that CS hasn't revisited heaps since 1961...But that's of course not the case.

Then kindly link me to the paper which describes his B-heaps; I'd love to read it.

[_delirium]

His specific B-heaps might indeed be novel; I'm not claiming he makes no contribution. I'm just objecting to the portion of his paper that claims that nobody in CS has ever thought of the idea of optimizing heaps for the properties of a modern computer's memory hierarchy. He seems to really believe Knuth's 1961 paper is the last word on the subject, or at least says so.

Fwiw, here's a widely cited 1996 paper that describes a different variety of block-aggregated heaps, "d-heaps", aimed mainly at cache-aware performance: http://lamarca.org/anthony/pubs/heaps.pdf

It's quite possible that no existing heap layouts solve his specific problem, but he could've at least acknowledged that there exist heaps newer than Knuth's, and that many of them specifically look at the influence of the memory hierarchy on performance.

[jemfinch]

That's a great paper, thanks for the reference.

[gaius]

Undergraduate CS education certainly hasn't.

[_delirium]

Hmm, my undergrad algorithms class at least mentioned the existence of cache effects, though it didn't really go into any detail. It had a bit of disclaimer along the lines of: for simplicity, we don't take into account caches in this class, but more modern models of computation do, and for real-world applications you might want to look up cache-aware algorithms.

[stcredzero]

Hmm, my undergrad algorithms class at least mentioned the existence of cache effects, though it didn't really go into any detail.

There should at least be exposure on the level of a walkthrough of the optimization of a real-world server. There was a concurrency optimization video posted to HN a couple of weeks ago.

[gaius]

In mine, we learnt about the hardware, the cache hierarchy and so on, completely separately from the algorithms and complexity theory. Two different classes, two professors. Probably they both knew it themselves, but it never occurred to them to cross-pollinate their course materials.