Optimizing application throughput continues to be a primary goal for any application developer seeking improved application performance. Before I can talk about the details of DBF scan ordering, there are some terms and concepts that must be discussed first. To understand DBF scan ordering, a base knowledge of Garbage Collection (GC), OpenJ9 GC policies, and…
Open J9’s Balanced GC policy is a region based, generational collector, which aims to provide a bound on worst case pause times, by eliminating the need for frequent global garbage collections. A more detailed description of how Balanced GC policy works, along with some of its advantages over the Gencon GC policy, can be found…
Background The Maximum Java Heap Size (Xmx) is the maximum amount of memory that Java application can uses. A lower Xmx value will cause a decrease in performance due to JVM has to force frequent garbage collections in order to free up space, also if the Xmx value is lower than the amount of live…
Background In order for Scavenger to find all live objects, it uses multiple threads and parallelizes the work as it traverses through the object trees. The number of working threads is dependent on the system: systems with more threads can use more threads to work on highly parallelized tasks. More information about this topic can…
Who am I, and why am I writing this? My name is Cedric Hansen, and I’m currently in the final week of my summer internship, working on the OpenJ9 GC team, in Ottawa. I’m writing this post to reflect on my experience, and discuss various aspects related to the work I did this summer. Coming…
