Skip to main content

How to select GC for java application

By

Which garbage collection(GC) algorithm suite for the application


If you don't have any strict pause-time requirements, first run your application and allow the VM to select a collector.
If necessary, adjust the heap size to improve performance. If the performance still doesn't meet
your performance, then use the specific collector and try.
Performance is dependent on the size of the heap, the amount of live data maintained by the
application, and the number and speed of available processors.
If the recommended collector doesn't achieve the desired performance, then first attempt to
adjust the heap and generation sizes to meet the desired goals. If performance is still
inadequate, then try a different collector: Use the concurrent collector to reduce pause-time,
and use the parallel collector to increase overall throughput on multiprocessor hardware.

Available Collector in Oracle JDK

-XX:+UseSerialGC
-XX:+UseParallelGC
-XX:+UseG1GC
-XX:+UseConcMarkSweepGC
-XX:UseZGC 

How to enable GC logs

Turning on GC Logging in Java 7 / 8

java -XX:+PrintGCDetails -XX:+PrintGCDateStamps - Xloggc: <file-path>

Turning on GC Logging in Java 9 and Up

java –Xlog:gc*:file=<file-path>:filecount=10,filesize=10M

Dynamically Turning on GC Logging in Java 9 and Up

jcmd <pid> VM.log what=gc output=<file-path>

How to analyze GC logs

[0.010s][info][gc] Using G1
[0.028s][info][gc] Periodic GC disabled
[0.584s][info][gc] GC(0) Pause Young (Normal) (G1 Evacuation Pause) 23M->4M(130M) 3.386ms
[0.885s][info][gc] GC(1) Pause Young (Normal) (GCLocker Initiated GC) 38M->6M(130M) 3.475ms
[1.782s][info][gc] GC(2) Pause Young (Concurrent Start) (Metadata GC Threshold) 77M->8M(130M) 3.816ms
[1.782s][info][gc] GC(3) Concurrent Cycle
[1.789s][info][gc] GC(3) Pause Remark 9M->9M(40M) 2.746ms
[1.791s][info][gc] GC(3) Pause Cleanup 9M->9M(40M) 0.043ms
[1.792s][info][gc] GC(3) Concurrent Cycle 9.942ms
[2.141s][info][gc] GC(4) Pause Young (Normal) (G1 Evacuation Pause) 27M->10M(40M) 5.106ms
[2.404s][info][gc] GC(5) Pause Young (Normal) (G1 Evacuation Pause) 29M->11M(40M) 2.537ms
[2.628s][info][gc] GC(6) Pause Young (Normal) (G1 Evacuation Pause) 29M->12M(40M) 3.846ms

This is an example of a CG log file , reading and analyzing this text file is a tedious task. There are some tools available for log analysis.

Labels:

Comments

Post a Comment

Popular posts from this blog

is not a JMX compliant Standard MBean

By
I got the fallowing exception and issue solved. If your are using MBean , MBean Interface and Implementation should be in same package, Otherwise use MXBean. javax.management.NotCompliantMBeanException: MBean class comlanka.rest.controller.DataManagerController does not implement DynamicMBean, and neither follows the Standard MBean conventions (javax.management.NotCompliantMBeanException: Class comlanka.rest.controller.DataManagerController is not a JMX compliant Standard MBean) nor the MXBean conventions (javax.management.NotCompliantMBeanException: comlanka.rest.controller.DataManagerController: Class comlanka.rest.controller.DataManagerController is not a JMX compliant MXBean)         at com.sun.jmx.mbeanserver.Introspector.checkCompliance(Introspector.java:176)         at com.sun.jmx.interceptor.DefaultMBeanServerInterceptor.registerMBean(DefaultMBeanServerInterceptor.java:317)         at com.sun.jmx.mbeanserver.JmxMBeanServer.registerMBean(JmxMBeanServer.java:522)        
Post a Comment
Read more

git Update failed

By
  Issue -  when you work with a large team, the git repository may have many branch creation and deletion operations, sometimes we may getting git update failed, when we try to update the whole repository. Solution - Tyr >  git fetch -p -p, --prune After fetching, remove any remote-tracking references that no longer exist on the remote. Tags are not subject to pruning if they are fetched only because of the default tag auto-following or due to a --tags option. However, if tags are fetched due to an explicit refspec (either on the command line or in the remote configuration, for example if the remote was cloned with the --mirror option), then they are also subject to pruning.
Post a Comment
Read more

Angular2 bind data only if form is submitted

By
How to bind data only if form is submitted in Angular2 This can be down with angular2 form handing with data-driven approach (User Angular  FormBuilder ). Template File <form [ngFormModel]='myForm' (ngSubmit)="onSubmit()"> <input type="text" [ngFormControl]="myForm.controls['userName']" /> <button type="submit">Submit</button> <button>Cancel</button> </form> <br>userName : {{originalUserName}} Angular Component Class export class AppComponent { myForm:ControlGroup; originalUserName:string; constructor(private _formBuilder:FormBuilder) { this.originalUserName = 'abc'; this.myForm = _formBuilder.group({ userName: [this.originalUserName] }); } onSubmit(form) { this.originalUserName = this.myForm.controls['userName'].value; } } GitHub Example Source
Post a Comment
Read more