Compiler Support for CRIU

[dsouzai]

Mode Change pre-checkpoint to post-restore

• -Xint to -Xjit/-Xaot (and vice versa); similarly with -Xnojit -Xnoaot to -Xjit/-Xaot (and vice versa) (Post-restore execution mode change semantics #16867)
• -Xjit to -Xnojit (and vice versa) (Post Restore Options Processing Continued #16838)
• -Xaot to -Xnoaot (Post Restore Options Processing Continued #16838)
• -Xnoaot to -Xaot (Handle -Xnoaot pre-checkpoint to -Xaot post-restore #16865)
• -Xnojit should also disable AOT load/compilation
• Add support for dynamic debug interpreter transition on restore (CRIU: Add support for dynamic debug interpreter transition on restore #17642)

Code Generation

• Generate Portable Code pre-checkpoint (Use Portable AOT setting for JIT compiles in CRIU mode #13092)
• -Xrs and -Xtrace (-Xrs & -Xtrace Compiler Support for CRIU #16839)
• -Xdump on exception
• -Xjit:enableGPU (Reset enableGPU if generating Portable Code #16861)

Runtime

• Options Processing Post-Restore (Compiler Options Processing Post Restore Design #16714)
• Performance Mode (-Xaggressive, -Xtune:virtualized, etc.) (Handle Performance Mode changes post-restore #16866)
• Update thresholds based on number of CPUs post-restore (Update thresholds based on number of CPUs post-restore #16858)
• Synchronize all compiler threads (compilation, sampler, iprofiler, etc.) (Synchronize compiler threads pre-checkpoint and post-restore #16859)
• Reset start and elapsed time (Post Restore Options Processing Part 4 #16852, Coordinate Sampler Thread across a Checkpoint/Restore #18541)
• Reset CPU utilization stats (Reset CPU utilization stats post-restore #16862)
• -XX:[+|-]PerfTool (Address -XX:[+|-]PerfTool / -Xjit:perfTool post-restore #16860)
• Free vmThread->aotVMwithThreadInfo->_sharedCache if AOT is disabled (Free vmThread->aotVMwithThreadInfo->_sharedCache if AOT is disabled post-restore #16864)
• Close files on checkpoint and re-open them on restore.

JITServer

• Enable JITServer in CRIU non-portable mode (Enable JITServer in CRIU non-portable mode #15674)
• Disable JITServer if -XX:-UseJITServer is specified in Non Portable Mode (Add support to disable JITServer and AOT post restore #16911)
• Regardless of CRIU mode (portable/non-portable), run in client mode before checkpoint but only enable JITServer if -XX:+UseJITServer is specified post restore. (Enable JITServer post-restore only if explicitly specified #17205)
• Investigate what might be needed if a user wishes to connect to the JITServer pre-checkpoint. (Enable JITServer post-restore only if explicitly specified #17205)

-Xshareclasses

• Post-restore -Xshareclasses change semantics (Post-restore -Xshareclasses change semantics #16868)
• Disable AOT if -Xshareclasses:disableOnRestore is specified post restore (Add support to disable JITServer and AOT post restore #16911)
• Use variable set by VM to determine if -Xshareclasses:disableOnRestore is set (Use sharedCacheAPI to determine -Xshareclasses:disableOnRestore #16972)

Other

• FSD support post restore (Compiler Support for Debug On Restore #18866)
• Investigate generating no AOT code pre-checkpoint. (Disable SCC/AOT and reduce counts when running with CRIU in containers #17253)

Testing

• Add JIT post-restore cmdline tests (Add JIT post-restore cmdline tests #17096)

Doc Updates

• CRIU Support Documentation Updates for 0.40 openj9-docs#1092