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Questions tagged [zgc]

A low latency garbage collector capable of handling heaps ranging from a few gigabytes to multi terabytes in size, with GC pause times not exceeding 10ms.

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The Java ZGC garbage collector USES a lot of memory

I built a simple application using Springboot.The ZGC garbage collector I use when deploying to a Linux server USES a lot of memory..I tried to limit the maximum heap memory to 500MB with Xmx500m, but the JAVA program still used more than 1GB. When…
greyWolf
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Getting 'allocation stall' when enabling ZGC

I am testing the new zgc garbage collector that was included in java 11 since it promises really low latency. Our application is a real-time service that creates and destroys many objects per second and it does it in a multi-threaded environment…
hveiga
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What exactly does the letter "Z" refer to in the name ZGC in JDK11?

I have heard that JDK 11 introduces a new garbage collector strategy named ZGC, but I cannot find what this stands for. What does the letter "Z" mean? Does it have any specific meaning?
Dolphin
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How to get zGC allocation stall times from the JVM?

How can I get the total allocation stall time due to zGC Garbage Collection in my Java application from the JVM (not the gc.log)? I saw this interesting answer: https://stackoverflow.com/a/13915440/992432, but looking at the the docs for…
Scott Skiles
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ZGC not supported with OpenJDK 11 and macOS?

I'm trying to run a spring boot application with ZGC Garbage Collector, with following JVM options passed in build.gradle: bootRun { jvmArgs = ["-XX:+UnlockExperimentalVMOptions", "-XX:+UseZGC", "-Xlog:gc*"] } While running an app (gradle…
Dargenn
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Is there an interface of read barrier in CoreCLR's standalone GC?

It seems that there's no interface of read barrier in CoreCLR. Recently I have implemented a pauseless GC in C. Here's my project: https://github.com/LizBing/Uboa-Garbage-Collector I tried customing a standalone GC library which can be used in .net.…
Lizbing
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JDK 17.0.1 ZGC allocation stall on fast allocation rate

We're using ZGC on JDK 17.0.1. The application successfully runs without unexpected GC stalls for a period of time, after which it gets into a state where the ZGC does not free much memory when the GC is being done. This results in multiple periodic…
0x00
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high cpu usage on openjdk zgc

I am trying to use zgc in product environment, so I updated jdk from jdk8 to openjdk 15, tomcat 8 to tomcat 8.5, and the gc related options, but the cpu usage goes to 1000+% after a few hours later of the jvm start(normal cpu usage should be…
xiaoxxcool
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Does the ZGC garbage collector support string deduplication?

Since it is not listed as an option at https://wiki.openjdk.java.net/display/zgc/Main I assume it is not supported. Some tests code made me wonder if it is supported?
Nick Russler
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java garbage collection about ZGC and G1

What is the difference between ZGC's relocation set and G1' s collection set in Java？I and learning JAVA's garbage collection and feel uncertain about this.
coffee
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Safepoint+stats log with None vmop operation in output JDK12

I am running application on the JDK12 with the -Xlog:safepoint+stats=debug:file=safepoint.log vm parameter to log the safepoint actions and running with ZGC. I have the problem to understand the log output: [1408.417s][debug][safepoint,stats] …
HPCS
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GC warning about "memory mappings per process" and JVM crash after migrating to java 17

We are migrating our java 8 application to java 17, and switching the GC from G1GC to ZGC. Our application is running as a container and the only difference between base-images of these two is the version of java. For example for java 17…
Arya
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ZGC out of memory error when moving from G1GC

I have an application in Java 17 configured like so: -Xms4096m -Xmx4096m -XX:+UseG1GC -XX:MaxMetaspaceSize=1024m It's a rather large web service that is pretty memory intensive over the years that's grown from a baseline other services…
RMSD
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What does ZGC SoftMaxHeapSize really do?

I understand the aim of SoftMaxHeapSize, but I can't find what it really does. Hopefully someone familiar with JDK internals can shed some light. Specifically, when the soft limit is reached: Does it simply change ZCollectionInterval and…
Aleksandr Dubinsky
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Make ZGC run often

ZGC runs not often enough. GC logs show that it runs once every 2-3 minutes for my application and because of this, my memory usage goes high between GC cycles (as high as 90%). After GC, it drops to as low as 20%. How to increase GC run's frequency…
viji
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