Add ability to sleep before checkpoint

This commit adds the ability to sleep before a checkpoint to allow the
compilation threads to compile the methods already present in the
compilation queue. It is important that the hook thread releases both
VM Access and the Compilation Monitor before sleeping; otherwise, the
compilation threads will not be able to empty the queue.

Signed-off-by: Irwin D'Souza <dsouzai.gh@gmail.com>

runtime/compiler/control/CompilationThread.cpp

@@ -2646,9 +2646,23 @@ void TR::CompilationInfo::prepareForCheckpoint()
    J9JavaVM   *vm       = _jitConfig->javaVM;
    J9VMThread *vmThread = vm->internalVMFunctions->currentVMThread(vm);
 
+   if (TR::Options::getCmdLineOptions()->getVerboseOption(TR_VerboseCheckpointRestore))
+      TR_VerboseLog::writeLineLocked(TR_Vlog_CHECKPOINT_RESTORE, "Preparing for checkpoint");
+
    {
    ReleaseVMAccessAndAcquireMonitor suspendCompThreadsForCheckpoint(vmThread, getCompilationMonitor());
 
+   if (TR::Options::_sleepMsBeforeCheckpoint)
+      {
+      if (TR::Options::getCmdLineOptions()->getVerboseOption(TR_VerboseCheckpointRestore))
+         TR_VerboseLog::writeLineLocked(TR_Vlog_CHECKPOINT_RESTORE, "Sleeping for %d ms", TR::Options::_sleepMsBeforeCheckpoint);
+
+      releaseCompMonitor(vmThread);
+      j9thread_sleep(static_cast<int64_t>(TR::Options::_sleepMsBeforeCheckpoint));
+      acquireCompMonitor(vmThread);
+      }
+
+
    if (shouldCheckpointBeInterrupted())
       return;
 
@@ -2713,10 +2727,14 @@ void TR::CompilationInfo::prepareForCheckpoint()
       }
    }
 
+   if (TR::Options::getCmdLineOptions()->getVerboseOption(TR_VerboseCheckpointRestore))
+      TR_VerboseLog::writeLineLocked(TR_Vlog_CHECKPOINT_RESTORE, "Ready for checkpoint");
    }
 
 void TR::CompilationInfo::prepareForRestore()
    {
+   if (TR::Options::getCmdLineOptions()->getVerboseOption(TR_VerboseCheckpointRestore))
+      TR_VerboseLog::writeLineLocked(TR_Vlog_CHECKPOINT_RESTORE, "Preparing for restore");
 
    {
    OMR::CriticalSection resumeCompThreadsForRestore(getCompilationMonitor());
@@ -2728,6 +2746,8 @@ void TR::CompilationInfo::prepareForRestore()
    resumeCompilationThread();
    }
 
+   if (TR::Options::getCmdLineOptions()->getVerboseOption(TR_VerboseCheckpointRestore))
+      TR_VerboseLog::writeLineLocked(TR_Vlog_CHECKPOINT_RESTORE, "Ready for restore");
    }
 #endif // #if defined(J9VM_OPT_CRIU_SUPPORT)
 

runtime/compiler/control/J9Options.cpp

@@ -135,6 +135,10 @@ int32_t J9::Options::_highActiveThreadThreshold = -1;
 int32_t J9::Options::_veryHighActiveThreadThreshold = -1;
 #endif /* defined(J9VM_OPT_JITSERVER) */
 
+#if defined(J9VM_OPT_CRIU_SUPPORT)
+int32_t J9::Options::_sleepMsBeforeCheckpoint = 1000; // 1 second
+#endif
+
 int32_t J9::Options::_interpreterSamplingThreshold = 300;
 int32_t J9::Options::_interpreterSamplingDivisor = TR_DEFAULT_INTERPRETER_SAMPLING_DIVISOR;
 int32_t J9::Options::_interpreterSamplingThresholdInStartupMode = TR_DEFAULT_INITIAL_BCOUNT; // 3000
@@ -991,6 +995,10 @@ TR::OptionTable OMR::Options::_feOptions[] = {
         TR::Options::setStaticNumeric, (intptr_t)&TR::Options::_sharedROMClassCacheNumPartitions, 0, "F%d", NOT_IN_SUBSET},
 #endif /* defined(J9VM_OPT_JITSERVER) */
    {"singleCache", "C\tallow only one code cache and one data cache to be allocated", RESET_JITCONFIG_RUNTIME_FLAG(J9JIT_GROW_CACHES) },
+#if defined(J9VM_OPT_CRIU_SUPPORT)
+   {"sleepMsBeforeCheckpoint=", " O<nnn>\tNumber of milliseconds to sleep before a checkpoint",
+        TR::Options::setStaticNumeric, (intptr_t)&TR::Options::_sleepMsBeforeCheckpoint,  0, "F%d" },
+#endif
    {"smallMethodBytecodeSizeThreshold=", "O<nnn> \tThreshold for determining small methods "
                                          "(measured in number of bytecodes)",
         TR::Options::setStaticNumeric, (intptr_t)&TR::Options::_smallMethodBytecodeSizeThreshold, 0, "F%d", NOT_IN_SUBSET},

runtime/compiler/control/J9Options.hpp

@@ -279,6 +279,10 @@ class OMR_EXTENSIBLE Options : public OMR::OptionsConnector
    static const uint32_t DEFAULT_JITSERVER_TIMEOUT = 30000; // ms
 #endif /* defined(J9VM_OPT_JITSERVER) */
 
+#if defined(J9VM_OPT_CRIU_SUPPORT)
+   static int32_t _sleepMsBeforeCheckpoint;
+#endif
+
    static int32_t _waitTimeToEnterIdleMode;
    static int32_t _waitTimeToEnterDeepIdleMode;
    static int32_t _waitTimeToExitStartupMode;