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adgjlsfhk1today at 12:36 AM2 repliesview on HN

A lot of the answer is that if you can do more work while generating less garbage (lower allocation rate) this problem basically solves itself. Basically every "high performance GC language" other than Java allows for "value type"/"struct"s which allow for way lower allocation rate, which puts a lot less pressure on the GC.


Replies

gf000today at 7:43 AM

How much less allocation rate? Value types are an important thing and fortunately they are coming to Java as well. But they don't decrease allocation rates nearly enough in every kind of software. They may be a necessity in games/certain computations/low-lat trading, but for a typical web server they don't matter all that much - people are using identity having objects in value typed languages the same way here. Especially that with thread local allocation buffers in Java single-use object allocations are not particularly expensive to begin with - live objects are evacuated and then the whole buffer is reset.

So unless you claim that there is no software in Go/C# where the GC is the bottleneck, no, the problem absolutely doesn't solve itself.

rossjudsontoday at 3:56 AM

And yet Java outruns pretty much all of them, because it doesn't actually allocate everything on the heap all of the time. And you've been able to declare and work with larger structures in raw memory for ... 20 years? You mostly don't need to, but sometimes you want to win benchmark wars.

And of course it's getting value types now, so it'll win there too. As well as vectors.