breaking-java-badly

Methodology and code for GC stress testing of OpenJDK 1.8 using different memory collectors under various synthetic loads. See PDFs in articles folder for detailed explanation.

FYI - code here currently uses tabs.

test execution

typical test execution usage from java_heap_tests folder (java files hould be compiled in place).

./t.sh 1 768 PCFrame02 1 12 ParallelOldGC test

• 12 tests numbered 1 thru 12 of 768 Million numbers are produced and consumed with a queue size limit of 1 Million are executed.

params are

<MCL in Millions> <Count in millions> <run id start> <run id end> <collector> <results folder>

output captured to specified results folder

GC analysis plot

Log analyzer in wally/wally1.py

simple usage -

python3 wally1.py gc8.log.file

params are

<JVM output log file> [-t '<plot title> -pause_ratio <float> -Xmx <heap size> -NewRatio <int>]'

output

png is generated with decorated name with 'png' added as prefix and suffix

major dependencies

1. OpenJDK 1.8 (tested)
2. matplotlib
3. python3