The G1 GC in JDK 9

Erik Helin, Senior Member of Technical Staff, Oracle

The G1 garbage collector is the default garbage collector in JDK 9. This session presents the goals of the G1 garbage collector, how it achieves them, and how it differs from the other garbage collectors in OpenJDK. The first part of the presentation explains the idea behind generational region-based memory management and how G1 can achieve good throughput while still meeting a pause-time goal. The second part then focuses on improvements made to G1 coming in JDK 9 and also gives a sneak peek at some of the features coming post-JDK 9.

[kings]

Really good intro before getting into detailed explanation.

[silpakandi]

Hi Eric, Can you please suggest any new performance tuning options for G1GC. We recently started migrating from CMS to G1GC which resulted in performance issues due to humongous objects. We went with 32M region size, still performance issue is not fixed. Please let me know if there are any special options to handle humongous objects.

[venkateshrasipuram]

Humongous object are the size of more than half of the region size. Let's say if my object some is 3MB and the region size is only 2MB. Where does this object gets allocated?? Will the size of the region gets resized automatically??

[samueldavidgomezramos]

Hi, what exactly compactly copied means?