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Comment by dermesser | Hacker News Reader

This is not true at all! Julia usually being JIT-compiled makes it very unsuitable for real time applications (and there's no reason why it should be great for it). GC is the least issue here, and I say that as a fan and daily user of Julia.

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Julia is already being used in a number of systems with varying levels of real-time-ness. It's early days for sure, but there's a bunch of progress. It turns out lots of "real time" applications actually just need fast code. JIT compile also can be overcome since in real time systems, you generally know all the code you are going to call so you can just make a .so with all of those bits compiled and know that nothing will need to be compiled at runtime.

Also on a related topic, the PR for parallel GC in Julia just merged 4 days ago (https://github.com/JuliaLang/julia/pull/48600), so GC is in the process of getting a bunch faster.

> Julia is already being used in a number of systems with varying levels of real-time-ness.

Any examples you could link to?

The coolest I know of is ASML putting Julia on their giant chip making machines https://www.youtube.com/watch?v=EafTuyy7apY. I think there's also work on putting Julia on satellites, but I don't have the details.

Note that in Julia 1.9 (rc3 currently) and thanks to `PrecompileTools.jl` being adopted by the vast majority of the packages, the compilation latency is a dead issue... (ok, it is moved to the package installation time...)

PrecompileTools.jl has definitely not been adopted by the "vast majority of packages" and compilation latency is not a dead issue. There's been huge progress, and the rate of progress on this is much higher than before, but let's not get ahead of ourselves.

That is not really true. People think that because they have spent time with Java which is excessively GC dependent. More modern GC languages such as Go and Julia have opted to use GCs in a far more conservative manner. They don't produce the exorbitant amount of garbage that Java produces. I've talked to NASA guys using Go for real time systems. They say it works great. GC doesn't need to be a problem if you do it right.

A JIT works perfectly alright for real time applications, PTC and Aicas are still in business.

What matters is how it is implemented, naturally a general purpose one won't do it.

Yes, I'm not saying it's not possible, but real time abilities were likely one of the least important aspects of Julia's design... So why shoehorn it into something it's not been designed for

After the 1st JIT-compilation (which here we treat as C++ static compilation), there is no compilation cost. As long as you avoid doing dynamic things (e.g. GC), there's a great case to be made for real time Julia.

Of course, but other than in C++ you need to use ways and means to achieve this - never hitting u compiled code - that are not very natural to Julia. Yes it may be possible to compile Julia code to binaries, but it obviously is neither straightforward nor widely used.

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