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Comment by szastamasta | Hacker News Reader

I see nothing particularly hard in utilising 32 cores. When I launch all the services in the project I’m working on my os has plenty work to schedule. Right now I have 3732 threads running on my machine. It’s totally separate question if OS can schedule so many threads effectively on so many cores, and how much coordination overhead there will be. But that’s just something we have to figure out and fix.

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The pure thread count is not that interesting. Running windows with pretty much just firefox open shows me about 5000 active threads, and and recent hardware shouldn't have a lot of problems with a 5digit number. Heavily loaded threads that actually require CPU power to execute are however definitely a different story.

I'm interested, what are you doing that can eat all those cores>

Anyone working on even a medium sized C++ project needs a very high end machine in order to compile. For large projects, 32 core work stations aren't crazy at all. Try building something like Firefox or Chromium on a quad core and you will see what I mean. The cost of the workstation is tiny compared to the cost of the engineer and you really don't want them to be waiting around for half their day (quite literally) because of a miserly equipment budget.

I talked about linux recompiles because sometimes you do need the cores; not arguing. But that's the long tail and many devs don't. I'm not against blowing cash if needed, but really it's about asking if there are more efficient ways. I guess we agree.

Compilation is largely memory bandwidth limited - some of the acceleration from cores might be that they have different memory channels rather than more CPUs.

M1 builds a lot faster than Intel CPUs even with fewer cores because of the memory bandwidth.

Really?? I am very surprised, do you have any pointers on this? Kind of important thing to me, thanks.

It's pretty easy to eat up cores when you're developing graphics rendering algorithms, which can be far more convenient and ergonomic to do on the CPU in a general purpose compiled language, and scaling out via plain old threads.

A CPU with so many general purpose high-perf cores that it manages to look like a GPU in terms of execution units count is a beautiful thing.

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