dasteg/javamemflame

javamemflame will generate a flame graph with Java memory allocation information.

Requirements

Java 11
Apache Maven

Build

mvn clean package

Usage

javamemflame will record memory allocation during the lifetime of the JVM with

java -javaagent:/path/to/javamemflame.jar ...

Then the information can be turned into a flame graph using

java -jar /path/to/javamemflame.jar javamemflame-pid.jfr

The result javamemflame-pid.svg can be viewed with any SVG viewer, like Firefox.

Agent options

The following agent options are supported.

delay=<number>: Delays the recording by the specified number of milliseconds.
duration=<number>: Record by the specified number of milliseconds.

Multiple options can be selected using the ',' character, like

java -javaagent:/path/to/javamemflame.jar=duration=1000,delay=500 ...

Main options

Output format

The output format of javamemflame can be controlled by

java -jar javamemflame.jar -o svg javamemflame-pid.jfr

Supported values

svg: Flame graph
txt: Text file

The text file can be turned into a flame graph using FlameGraph

/path/to/FlameGraph/flamegraph.pl --flamechart --color=java javamemflame-pid.txt > javamemflame-pid.svg

Threads

javamemflame can use multiple threads to process the .jfr file faster by

java -jar javamemflame.jar -t 8 javamemflame-pid.jfr

Cut off

javamemflame can filter out allocations under the specified number, and merge them together under a Filtered category. F.ex. cut off at 100 MB

java -jar javamemflame.jar -c 100000000 javamemflame-pid.jfr

Title

The flame graph can be given a title using

java -jar javamemflame.jar --title "My FlameGraph" javamemflame-pid.jfr

Count

The number of allocation counts, instead of their combined size, can be done using

java -jar javamemflame.jar -n javamemflame-pid.jfr

JFR files

Multiple .jfr files can be specified on the command line and their information will be merged

java -jar javamemflame.jar javamemflame-pid1.jfr javamemflame-pid2.jfr

Package filtering

javamemflame can filter on package names, and only include their information

java -jar javamemflame.jar javamemflame-pid.jfr package[,package]*

Thanks to

Brendan Gregg

License

This project is licensed under EPL v2. See the LICENSE file.

dasteg / javamemflame