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A comment on ZGC: A Scalable Low-Latency Garbage Collector [video].

Re:ZGC: A Scalable Low-Latency Garbage Collector [video] by bradleyjg on Sunday October 28, 2018 @11:38AM (#18321095)
The talk has a lot of interesting technical details, but the bottom line for java developers or jvm sys admins is that the new GC trades off throughput for reduced maximum pause times (current goal is 10ms max pause time, longer term goal is less than 1 ms).

The upshot of that is that you probably don't want to swap to this unless you use a relatively large heap (at least 32 GB, maybe more), because below that level the STW latency of the other GC options aren't generally speaking bad enough to be worth the trade-off.

Also if latency is a big concern for you and you've got dollars to spend consider Azul zing as well. (That part isn’t from the talk.)

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Re:ZGC: A Scalable Low-Latency Garbage Collector [video] by gbasin on Sunday October 28, 2018 @04:44PM (#18323049)
Yep, this. Although to be fair, Zing is pretty good but not a panacea. It causes latencies to increase across the board -- probably due to increased allocation times, or maybe messing with the cache
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Re:ZGC: A Scalable Low-Latency Garbage Collector [video] by chrisseaton on Sunday October 28, 2018 @06:43PM (#18323676)
> probably due to increased allocation times

Doesn’t C4 still use a thread-local bump allocator? How does that increase allocation time?

I would think it’s much more likely to be the complex barriers.

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Re:ZGC: A Scalable Low-Latency Garbage Collector [video] by gbasin on Sunday November 04, 2018 @06:34PM (#18378663)
Yes you're probably right. I haven't dug much into it myself
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Re:ZGC: A Scalable Low-Latency Garbage Collector [video] by giltene on Saturday November 10, 2018 @01:54PM (#18422837)
If you did (dig into it yourself), you'd quickly find out that the urban myth about Zing somehow hurting latencies across the board is plain wrong. In fact, these days it tends to be percievably faster (in both latency and throughput) in about 70-80% of the workload we encounter. Certainly when compared to G1GC and CMS, and often even when compared to ParallelGC... E.g. it is typicaly >10% faster at things like Cassandra, Spark (TPC-DS), LMAX Disruptor workloads, etc. etc. etc.
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