gcat

meaning [gc cat], a java gc log analyser, currently support CMS + ParNew gc collector.

Build

mvn package

Usage

java -cp  gcat.jar io.gcat.Gcat {gc.log}

Measure

1. gc duration
2. gc count
3. avg|max gc pause time
4. avg|min gc interval
5. JVM Heap Size 年轻代，老年代，meta各区的总大小，峰值大小
6. 吞吐量
7. 延迟（平均暂停时间，最大暂停时间）
8. Gc暂停时长分布
9. CMS各阶段耗时 累计时长、占比
10. gc原因占比

example output:

Heap GC Time:
	avg: 72 ms
	max: 25490 ms(at 2019-05-09T02:05:30.342+08, epoch: 1557338730342)
Heap GC Interval:
	avg: 3551 ms
	min: 10 ms(at 2019-05-09T05:06:37.091+08, epoch: 1557349597091)

CMS+ParNew algorithm

gc duration: duration between first valid gc log timestamp to the last valid gc log timestamp.

gc count: yong gc + old gc count.

Reference

Minor GC、Major GC和Full GC之间的区别

Major GC和Full GC的区别是什么？触发条件呢？

Java之CMS GC的7个阶段

快速解读GC日志

Java GC 日志格式理解小结

GC 日志格式

Understanding the Java Garbage Collection Log

Understanding Garbage Collection Logs

浅谈 G1 GC 日志格式

Useful JVM Flags – Part 8 (GC Logging)

JVM GC 日志详解