Java – why not more boring GC

Except Azul, all GCS I know are concurrent, but at least there are some small worldwide components Why isn't there more GC like Azul?

Does Azul patent the technology to the extent that it is impossible?

Or is the read / write barrier required to do useless operations such an overhead that it is impractical for most workloads?

Solution

Based on the Azul whitepaper on C4, it seems that C4 is a very new technology. The implementation of an algorithm released in 2005 is first on customized hardware, and then transplanted to Linux on X86. The JVM implementation is very close to the kernel VM system

Because openjdk / hotspot is widely used in many platforms and major production workloads, it tends to become slower when adopting major algorithm innovations (tend to timsort is a good example) Java 8 version has introduced the first overhaul of GC system for many years (with the elimination of permgen). If cross platform or abstract implementation can be realized without significantly reducing the improvement of JVM bookkeeping internal structure, it may be improved. Try to use openjdk / hotspot in the upcoming version