/**
* Method to provide a gross level of synchronization with the target monitored jvm.
*
* <p>gross synchronization works by polling for the hotspot.rt.hrt.ticks counter, which is the
* last counter created by the StatSampler initialization code. The counter is updated when the
* watcher thread starts scheduling tasks, which is the last thing done in vm initialization.
*/
protected void synchWithTarget(Map<String, Monitor> map) throws MonitorException {
/*
* synch must happen with syncWaitMs from now. Default is 5 seconds,
* which is reasonabally generous and should provide for extreme
* situations like startup delays due to allocation of large ISM heaps.
*/
long timeLimit = System.currentTimeMillis() + syncWaitMs;
String name = "hotspot.rt.hrt.ticks";
LongMonitor ticks = (LongMonitor) pollFor(map, name, timeLimit);
/*
* loop waiting for the ticks counter to be non zero. This is
* an indication that the jvm is initialized.
*/
log("synchWithTarget: " + lvmid + " ");
while (ticks.longValue() == 0) {
log(".");
try {
Thread.sleep(20);
} catch (InterruptedException e) {
}
if (System.currentTimeMillis() > timeLimit) {
lognl("failed: " + lvmid);
throw new MonitorException("Could Not Synchronize with target");
}
}
lognl("success: " + lvmid);
}
/**
* Method to poll the instrumentation memory for a counter with the given name. The polling period
* is bounded by the timeLimit argument.
*/
protected Monitor pollFor(Map<String, Monitor> map, String name, long timeLimit)
throws MonitorException {
Monitor monitor = null;
log("polling for: " + lvmid + "," + name + " ");
pollForEntry = nextEntry;
while ((monitor = map.get(name)) == null) {
log(".");
try {
Thread.sleep(20);
} catch (InterruptedException e) {
}
long t = System.currentTimeMillis();
if ((t > timeLimit) || (overflow.intValue() > 0)) {
lognl("failed: " + lvmid + "," + name);
dumpAll(map, lvmid);
throw new MonitorException("Could not find expected counter");
}
getNewMonitors(map);
}
lognl("success: " + lvmid + "," + name);
return monitor;
}
