ForkJoinPool alignment

 ➜  jol hg summary
parent: 91:b5653b56d154 tip
 7901803: JOL should try instantiating the sample instances with non-default constructors
branch: default
commit: (clean)
update: (current)
 
 ➜  jol java -jar /Users/azolotko/.m2/repository/org/openjdk/jol/jol-cli/0.7-SNAPSHOT/jol-cli-0.7-SNAPSHOT-full.jar estimates java.util.concurrent.ForkJoinPool 
# WARNING: Unable to attach Serviceability Agent. You can try again with escalated privileges. Two options: a) use -Djol.tryWithSudo=true to try with sudo; b) echo 0 | sudo tee /proc/sys/kernel/yama/ptrace_scope
# Running 64-bit HotSpot VM.
# Using compressed oop with 3-bit shift.
# Using compressed klass with 3-bit shift.
# WARNING | Compressed references base/shifts are guessed by the experiment!
# WARNING | Therefore, computed addresses are just guesses, and ARE NOT RELIABLE.
# WARNING | Make sure to attach Serviceability Agent to get the reliable addresses.
# Objects are 8 bytes aligned.
# Field sizes by type: 4, 1, 1, 2, 2, 4, 4, 8, 8 [bytes]
# Array element sizes: 4, 1, 1, 2, 2, 4, 4, 8, 8 [bytes]

***** 32-bit VM: **********************************************************
Error while accessing @Contended value: class org.openjdk.jol.vm.ContendedSupport cannot access interface jdk.internal.vm.annotation.Contended (in module java.base) because module java.base does not export jdk.internal.vm.annotation to unnamed module @128d2484

java.util.concurrent.ForkJoinPool object internals:
 OFFSET  SIZE                        TYPE DESCRIPTION                    VALUE
      0     8                             (object header)                N/A
      8     8                        long ForkJoinPool.stealCount        N/A
     16     8                        long ForkJoinPool.keepAlive         N/A
     24     4                         int ForkJoinPool.indexSeed         N/A
     28     4                         int ForkJoinPool.bounds            N/A
     32     4                         int ForkJoinPool.mode              N/A
     36     4                 WorkQueue[] ForkJoinPool.workQueues        N/A
     40     4                      String ForkJoinPool.workerNamePrefix  N/A
     44     4 ForkJoinWorkerThreadFactory ForkJoinPool.factory           N/A
     48     4    UncaughtExceptionHandler ForkJoinPool.ueh               N/A
     52     4                   Predicate ForkJoinPool.saturate          N/A
     56   128                             (alignment/padding gap)        N/A
    184     8                        long ForkJoinPool.ctl               N/A
    192   128                             (loss due to the next object alignment)
Instance size: 320 bytes
Space losses: 128 bytes internal + 128 bytes external = 256 bytes total

***** 64-bit VM: **********************************************************
java.util.concurrent.ForkJoinPool object internals:
 OFFSET  SIZE                        TYPE DESCRIPTION                    VALUE
      0    16                             (object header)                N/A
     16     8                        long ForkJoinPool.stealCount        N/A
     24     8                        long ForkJoinPool.keepAlive         N/A
     32     4                         int ForkJoinPool.indexSeed         N/A
     36     4                         int ForkJoinPool.bounds            N/A
     40     4                         int ForkJoinPool.mode              N/A
     44     4                             (alignment/padding gap)        N/A
     48     8                 WorkQueue[] ForkJoinPool.workQueues        N/A
     56     8                      String ForkJoinPool.workerNamePrefix  N/A
     64     8 ForkJoinWorkerThreadFactory ForkJoinPool.factory           N/A
     72     8    UncaughtExceptionHandler ForkJoinPool.ueh               N/A
     80     8                   Predicate ForkJoinPool.saturate          N/A
     88   128                             (alignment/padding gap)        N/A
    216     8                        long ForkJoinPool.ctl               N/A
    224   128                             (loss due to the next object alignment)
Instance size: 352 bytes
Space losses: 132 bytes internal + 128 bytes external = 260 bytes total

***** 64-bit VM, compressed references enabled: ***************************
java.util.concurrent.ForkJoinPool object internals:
 OFFSET  SIZE                        TYPE DESCRIPTION                    VALUE
      0    12                             (object header)                N/A
     12     4                         int ForkJoinPool.indexSeed         N/A
     16     8                        long ForkJoinPool.stealCount        N/A
     24     8                        long ForkJoinPool.keepAlive         N/A
     32     4                         int ForkJoinPool.bounds            N/A
     36     4                         int ForkJoinPool.mode              N/A
     40     4                 WorkQueue[] ForkJoinPool.workQueues        N/A
     44     4                      String ForkJoinPool.workerNamePrefix  N/A
     48     4 ForkJoinWorkerThreadFactory ForkJoinPool.factory           N/A
     52     4    UncaughtExceptionHandler ForkJoinPool.ueh               N/A
     56     4                   Predicate ForkJoinPool.saturate          N/A
     60   132                             (alignment/padding gap)        N/A
    192     8                        long ForkJoinPool.ctl               N/A
    200   128                             (loss due to the next object alignment)
Instance size: 328 bytes
Space losses: 132 bytes internal + 128 bytes external = 260 bytes total

***** 64-bit VM, compressed references enabled, 16-byte align: ************
java.util.concurrent.ForkJoinPool object internals:
 OFFSET  SIZE                        TYPE DESCRIPTION                    VALUE
      0    12                             (object header)                N/A
     12     4                         int ForkJoinPool.indexSeed         N/A
     16     8                        long ForkJoinPool.stealCount        N/A
     24     8                        long ForkJoinPool.keepAlive         N/A
     32     4                         int ForkJoinPool.bounds            N/A
     36     4                         int ForkJoinPool.mode              N/A
     40     4                 WorkQueue[] ForkJoinPool.workQueues        N/A
     44     4                      String ForkJoinPool.workerNamePrefix  N/A
     48     4 ForkJoinWorkerThreadFactory ForkJoinPool.factory           N/A
     52     4    UncaughtExceptionHandler ForkJoinPool.ueh               N/A
     56     4                   Predicate ForkJoinPool.saturate          N/A
     60   132                             (alignment/padding gap)        N/A
    192     8                        long ForkJoinPool.ctl               N/A
    200   136                             (loss due to the next object alignment)
Instance size: 336 bytes
Space losses: 132 bytes internal + 136 bytes external = 268 bytes total