Virtual Threads: a Liberty case study

Catch up with Vijay Sundaresan and Gary DeVal our top performance leads. 

https://www.infoq.com/articles/java-virtual-threads-a-case-study/ 

• Virtual threads are an important advancement in Java concurrent programming, but they do not offer a clear advantage over Open Liberty’s existing autonomic thread pool for running typical cloud-native Java workloads.
• For CPU-intensive workloads, throughput is lower with virtual threads than with Open Liberty’s thread pool for currently unclear reasons.
• Virtual thread ramp-up time from idle to maximum throughput is quicker than Open Liberty’s thread pool due to its thread-per-request model.
• Memory footprint in Open Liberty deployments can vary greatly based on factors like application design, workload level, and garbage collection behavior, so the reduced footprint of virtual threads may not result in an overall reduction in memory used.
• Virtual threads showed some unexpected performance issues in some use cases that Java developers should be aware of. We are working  with the OpenJDK Community to investigate the root cause and to try to resolve the issues.