CRIU j9time_nano_time skips the elapsed time between Checkpoint/Restore

[JasonFengJ9]

Added a field checkpointRestoreTimeDelta within J9PortLibrary, which is to be set the time delta between Checkpoint and Restore of j9time_nano_time() return values;
Updated trace points to record the actual j9time_nano_time() values.

This is first part to address the issue #14211, for System.nanoTime().

Tested w/ following code snippet:

long beforeSnapshot = System.nanoTime();
System.out.println("System.nanoTime() before snapshot: " + beforeSnapshot);
criuSupport.checkpointJVM();
long afterRestore = System.nanoTime();
System.out.println("System.nanoTime() after restore: " + afterRestore + ", the delta is: " + (afterRestore - beforeSnapshot));

Snapshot run w/ -Xtrace:print={j9criu}

System.nanoTime() before snapshot: 1923502764451872
20:46:59.339 0x1aa00          j9criu.7        - Before checkpoint criu_dump(), beforeSnapshot = 1923502857103461

Multiple restores

20:47:03.515 0x1aa00          j9criu.8        - After checkpoint criu_dump(), afterRestore = 1923507032477031, snapshotRestoreTimeDelta = 4175373570
System.nanoTime() after restore: 1923502933280333, the delta is: 168828461

20:47:16.307 0x1aa00          j9criu.8        - After checkpoint criu_dump(), afterRestore = 1923519824763404, snapshotRestoreTimeDelta = 16967659943
System.nanoTime() after restore: 1923502929966245, the delta is: 165514373

20:47:18.447 0x1aa00          j9criu.8        - After checkpoint criu_dump(), afterRestore = 1923521964335134, snapshotRestoreTimeDelta = 19107231673
System.nanoTime() after restore: 1923502946667346, the delta is: 182215474

Signed-off-by: Jason Feng fengj@ca.ibm.com

[tajila]

can you add test cases for this?

[JasonFengJ9]

can you add test cases for this?

Added a test, will need a rebase after merging #14824.

[JasonFengJ9]

Resolved the merge conflict.
@tajila this is ready for another look.

[tajila]

Jenkins test sanity xlinuxcriu jdk11

[tajila]

Jenkins test sanity win jdk8