RFR: 8319900: Recursive lightweight locking: riscv64 implementation

[Fei Yang]

On Wed, 24 Jan 2024 14:09:21 GMT, Gui Cao <gcao at openjdk.org> wrote:

> Implementation of recursive lightweight JDK-8319796 for linux-riscv64.
> 
> ### Correctness testing:
> 
> - [x]  Run tier1-3, hotspot:tier4 tests with -XX:LockingMode=1 & -XX:LockingMode=2 on LicheePI 4A (release)
> - [x]  Run tier1-3 tests with -XX:LockingMode=1 & -XX:LockingMode=2 on qemu 8.1.0 (fastdebug)
> 
> ### JMH tested on LicheePI 4A:
> 
> 
> Before (LockingMode = 2):
> 
> Benchmark                                (innerCount)  Mode  Cnt       Score      Error  Units
> LockUnlock.testContendedLock                      100  avgt   12     281.603 ±    2.626  ns/op
> LockUnlock.testRecursiveLockUnlock                100  avgt   12  196373.917 ± 4669.241  ns/op
> LockUnlock.testRecursiveSynchronization           100  avgt   12     274.492 ±    6.049  ns/op
> LockUnlock.testSerialLockUnlock                   100  avgt   12   11516.092 ±   69.964  ns/op
> LockUnlock.testSimpleLockUnlock                   100  avgt   12   11490.789 ±   58.833  ns/op
> 
> After (LockingMode = 2):
> 
> Benchmark                                (innerCount)  Mode  Cnt      Score    Error  Units
> LockUnlock.testContendedLock                      100  avgt   12    307.013 ±  3.259  ns/op
> LockUnlock.testRecursiveLockUnlock                100  avgt   12  59047.222 ± 94.748  ns/op
> LockUnlock.testRecursiveSynchronization           100  avgt   12    259.789 ±  1.698  ns/op
> LockUnlock.testSerialLockUnlock                   100  avgt   12   6055.775 ± 13.518  ns/op
> LockUnlock.testSimpleLockUnlock                   100  avgt   12   6090.986 ± 67.179  ns/op
> 
> 
> 
> Before (LockingMode = 1):
> 
> Benchmark                                (innerCount)  Mode  Cnt      Score     Error  Units
> LockUnlock.testContendedLock                      100  avgt   12    286.144 ±   2.490  ns/op
> LockUnlock.testRecursiveLockUnlock                100  avgt   12  68058.259 ± 286.262  ns/op
> LockUnlock.testRecursiveSynchronization           100  avgt   12    263.132 ±   4.075  ns/op
> LockUnlock.testSerialLockUnlock                   100  avgt   12   7521.777 ±  35.193  ns/op
> LockUnlock.testSimpleLockUnlock                   100  avgt   12   7522.480 ±  26.310  ns/op
> 
> After (LockingMode = 1):
> 
> Benchmark                                (innerCount)  Mode  Cnt      Score     Error  Units
> LockUnlock.testContendedLock                      100  avgt   12    289.034 ±   5.821  ns/op
> LockUnlock.testRecursiveLockUnlock                100  avgt   12  68474.370 ± 495.135  ns/op
> LockUnlock.testRecursiveSynchronization           100  avgt   12    261.052 ±   4.560  ns/op
> Loc...

This looks pretty good. Thanks.

-------------

Marked as reviewed by fyang (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/17554#pullrequestreview-1899965559