001-杨飞.pdf

1、OpenJDK on RISC-V UpdateFei Yang PLCT Lab,ISCASOpenJDK Reviewer&RISC-V Port Project Leadhttps:/openjdk.org/census#fyangProject GoalTo provide first class Java support on RISC-V 64-bit architecture(RV64GCV)https:/openjdk.org/projects/riscv-porthttps:/mail.openjdk.org/pipermail/riscv-port-devProject T

2、imelineMar 2022-Upstreamed to OpenJDK mainline-https:/ of JEP 422:Linux/RISC-V Port)-Available in JDK 19-23(including JDK 21 LTS)Jul 2023-Backported to OpenJDK 17u master-https:/ of JEP 422:Linux/RISC-V Port)-Available in JDK 17.0.9+release Feb 2024-Backported to riscv-port-11u project repo-https:/

3、of JEP 422:Linux/RISC-V Port)-Placeholder:https:/ full-featured Java portNew features supported-New RISC-V extensions support-New Lightweight Locking-Virtual Threads-Vector API(Incubator)-Foreign Function&Memory API-Generational ZGC&ShenandoahGC-Various performance tunings*Contributions by:ISCAS,Riv

4、os,Huawei,Alibaba,*300+upstream PR reviewed&merged,mostly RISC-V related.New RISC-V extensions supportedIMAFDCVZbaZbbZbsZic64bZicbomZicbozZvbbZvknZvknedZacasZtsoZihintpauseZfhZvfhZcbNew RISC-V extensions supported-https:/www.kernel.org/doc/html/v6.5-rc2/riscv/hwprobe.htmlRISC-V Hardware Probing Sysc

5、all:New RISC-V extensions supported-https:/ tunning:New Lightweight LockingThree different locking modes in latest HotSpot JVM(-XX:LockingMode):LM_MONITOR :Heavy monitors only(the same as current-XX:+UseHeavyMonitors);LM_LEGACY :Legacy stack-locking,with monitors as second tier;LM_LIGHTWEIGHT:New li

6、ghtweight locking,with monitors as second tier(current default);JavaSynchronizedBlockLM_LEGACY LockingLM_LIGHTWEIGHTLockingLM_MONITOR LockingInflationNew Lightweight LockingProblem with LM_LEGACY locking modeJava Object HeaderExample of a locked object(stacking locking mode)Lock-wordstates and layou