Dmitry Chuyko

Biased locking was removed from OpenJDK HotSpot JVM some time ago. This move had its reasons, but it resulted in a number of significant performance degradations in existing code. Thus, when non-contended locking optimization can be added, it still benefits virtual machines. Parallel stop-the-world garbage collection is one of the earliest GC variants in HotSpot, and yet it is the best choice in terms of high throughput. SubstrateVM which powers GraalVM native image supports synchronization monitors and offers serial stop-the-world GC as a basic collector. Due to the increased popularity of pre-compilation and its support in modern frameworks, it is remarkable how playing classical optimization pieces helps to improve the performance of such code. BellSoft recently put locking and garbage collection enhancements for public review. It is interesting that within GraalVM project both were implemented in Java. We'll explore implementation details, benchmark results, and application benefits.

BellSoft created tiny containers based on Alpine Linux. But Alpine has its cons: musl sometimes performs worse than glibc, LTS support is not long enough. So we developed Alpaca Linux based on Alpine. Alpaca is more performant and secure, has longer LTS support, and is perfect for Java deployment.

The size matters when it comes to containers: they should be small but performant. BellSoft engineers came up with the solution and integrated the Alpine musl port into JDK 16. We made containers based on Alpine Linux and immediately understood that we hit the spot. These containers are still in demand and keep gaining popularity. Alpine Linux is based on musl. There is usually no difference in performance, but in some cases, musl is less efficient than glibc. The problem is that any Linux distro is made for general purposes, and Linux engineers don’t have Java in mind when developing them. In addition, LTS support for Linux kernel and OpenJDK is longer than that for Alpine Linux, which leads to a more frequent migration between OS versions within one Java release. We want to make sure that Java LTS visions are stable within the environments we offer. This is why we created our own distribution, Alpaca Linux, based on Alpine. Alpaca Linux has a longer support cycle and includes musl-perf and other components to boost the performance of apps, including Java-based ones. In my talk, I will describe the differences between Alpaca and Alpine and show the results of the benchmarks. I will also tell you about the Alpaca release cycle and how to get hands on with this new Linux distro. You will find out how to boost the performance and security of Java deployment with Alpaca Linux. All in all, I think that this is the beginning of a beautiful friendship between Alpaca and Java.

Container images based on Alpine Linux have been around for some time. You can calculate the real cost savings from using small containers, which we will do. And now it's time to have them as an official flavor of Java Runtime with new JEP 386: Alpine Linux Port. The new port has its own subtleties, which we will consider in the context of microservices development.

BellSoft is the company behind JEP 386 and we would like to share our work in the OpenJDK community. We have long been providing Liberica JDK Docker images on top of Alpine Linux. It really helps our users and therefore remains the most popular choice.