Questions tagged [concurrent-mark-sweep]

Concurrent-mark-sweep is a garbage collection algorithm, known for its use on the Java Virtual Machine, which can reduce stop-the-world times on machines with limited resources.

Concurrent-mark-sweep is a garbage collection algorithm, known for its use on the Java Virtual Machine, which can reduce stop-the-world times on machines with limited resources; this is an attempt to reduce response times related to GC activity.

However, it can result in fragmentation of the old generation, and can fall back to older methods. It is not efficient on large heaps, since the mark phase is dependent on the size of live objects, and the sweep phase can traverse the entire heap.

Under concurrent-mark-sweep, most garbage collection activity is performed concurrently, i.e., while the application threads are running, to keep garbage collection-induced pauses short. This is in contrast to a simple stop-the-world garbage collector which completely halts execution of the program to run a collection cycle.

To enable, use the JVM argument -XX:+UseConcMarkSweepGC .

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CMS-concurrent-sweep taking long time

I have a windows machine running on KVM and I am running a java application (Using CMS GC) on the windows machine. The application was behaving very slow, so I checked the GC logs. The max heap size was 5 GB, but in the gc logs, I could find that…
dVader
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java -XX:+PrintFlagsFinal -version | grep RAMPercentage --> Should not MinRAMPercentage be less than MaxRAMPercentage?

$ java -XX:+PrintFlagsFinal -version | grep RAMPercentage double InitialRAMPercentage = 1.562500 {product} double MaxRAMPercentage = 25.000000 …
Vamsh
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What is the concrete job in "final remark" about CMS?

From plumbr's cookbook, I have seen that what init mark, concurrent mark, concurrent preclean and concurrent abortable preclean do. init mark concurrent mark concurrent preclean But I can't get the real job about the "final remark". Only…
lxyscls
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Single server with multiple JVMs and multiple GC algorithms

I have a single linux application server with 4 JVMs on it. The GC Algorithm that I use on them is CMS. Can i change the GC algorithm of two of those JVMs to G1GC ? Is there any negative impact by doing so ?
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JMV GC logs don't show CMS events

This is a capture of the GC activity: 2016-12-28T08:05:47.072-0800: 53612.476: [Full GC (System.gc()) Before GC: Statistics for BinaryTreeDictionary: ------------------------------------ Total Free Space: 2492815068 Max Chunk Size:…
benji
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High frequency of CMS tenured phases even when Old/Young gen have ample space

I acknowledge up front that this issue is very similar to: high-number-of-cms-mark/remark-pauses-even-though-old-gen-is-not-half-full and tenured-collection-starting-for-no-apparent-reason. I'm posting because 1. those threads are over 1yr old, and…
kmarx
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Is it CMS-concurrent-preclean abort causing time consuming execution of CMS-concurrent-sweep?

java -version java version "1.6.0_21" Java(TM) SE Runtime Environment (build 1.6.0_21-b07) Java HotSpot(TM) 64-Bit Server VM (build 17.0-b17, mixed mode) jvm configuration : -server -XX:+DoEscapeAnalysis -XX:+CMSParallelRemarkEnabled …
Steephen
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High Number of CMS mark remark pauses even though Old gen is not half full

I am trying to understand the cause for high number of CMS marks and remarks(other phases as well) averaging around 700ms even though the old gen is not even half full.Following are the GC configurations and stats from GCViewer. -Xms3g -Xmx3g…
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Java Garbage Collector Allocation Failure

I am running my java application on machine having 8GB Memory and 4 CPU. But after running application for longer period with stress testing, Garbage collector problems are observed as memory is completely full and seems that gc cycles taking longer…
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Parallel promotion failures... Whats the cause?

I'm running a java program using 3GB heap space. After a while I notice this in the gc logs. Application time: 0.8263100 seconds 2015-03-13T07:24:49.065-0700: 77177.620: [GC Before GC: Statistics for BinaryTreeDictionary: Total Free Space:…
Vishal
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CMS Garbage Collection taking too long

One of our customers runs into major performance problems which seem to be caused by long garbage collection runs and I don't know what to do about it... Java version: 1.7.0_67 JVM args: -Xms10240m -Xmx16386m -XX:NewSize=2048m -XX:MaxPermSize=150m…
Gishan
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