Lately, I noticed that IntelliJ started to pause for quite some time during it’s GC cycles, and that it was very frequent when I was editing three files (over 1.2k LOC each) split vertically.
The current version of IntelliJ runs on a bundled version of Java 1.8, who’s default garbage collector is Parallel GC. While this works for most people, it didn’t for me.
After a ton of reading up on how GC works, and the fine tuning parameters for G1, I put it to use. Here’s a copy of my idea.vmoptions file:
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| -Xmx2048m | |
| -Xss256k | |
| -XX:+UseG1GC | |
| -XX:InitiatingHeapOccupancyPercent=65 | |
| -XX:G1HeapRegionSize=16m | |
| -XX:MaxGCPauseMillis=100 |
There was an instant performance boost in the IDE – it was far more responsive than ever before. The pauses have disappeared, and it’s super snappy :)
Note: As a general rule of thumb, don’t increase the maximum memory allocated to the IDE beyond 2 gigabytes – it’s just not worth it.