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by dwohnitmok 2412 days ago
It's interesting to see how other GCs try to handle this. In particular the JVM's (awesome) new Shenandoah low-latency GC has a ShenandoahAllocSpikeFactor option precisely to deal with this kind of situation, where you can specify what percentage of the heap you're willing to sacrifice in a spike in allocation rates before the GC starts running wild trying to collect garbage.

The trade-off of the knob-less approach of Go's GC I suppose.
1 comments
apta 2412 days ago
The JVM offers state of the art GCs, which allows for selecting the best tool for the job (throughput, latency, large heaps, etc.).

This is unlike the golang gc, which is tuned for latency at the expense of throughput, with no way of modifying its behavior without resorting to hacks like the article in the post.

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dwohnitmok 2412 days ago
To Go's credit, it predates Shenandoah and ZGC, before which your only real option for low-latency GC on the JVM was Zing, which I don't think had too many people using it (I certainly have no personal experience with it). I can't say whether they were inspired by Go, but I do think that Go is responsible for bringing the desirability of low-latency GC, even at potentially high cost to throughput, to the forefront of the greater programming community's attention.
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pjmlp 2411 days ago
They could offer other ways to manage memory manually instead of just escape analysis, like GC enabled systems languages, but that is not the nature of Go's design.
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astral303 2411 days ago
Do you not consider G1 a low latency GC?
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dwohnitmok 2411 days ago
When considering latency, it's still not in the same league as Shenandoah and ZGC. We still had occasional GC times over a second with G1 on some production systems several years ago IIRC.
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tus88 2411 days ago
Except when the best tool for the job is a language without GC at all.
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Thaxll 2412 days ago
Yes you can modify GC behaviour and it's one env variable, the fact that twitch didn't use it makes no sense.
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MaulingMonkey 2412 days ago
The original blog post[1] does mention GOGC, and a list of pitfalls that made them prefer ballast / the pending heap size proposal[2] over it. Are they in error? Or do you find their reasoning unconvincing?

[1] https://blog.twitch.tv/en/2019/04/10/go-memory-ballast-how-i...

[2] https://github.com/golang/go/issues/23044

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