/**
* 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 repair the 1.4.2 parallel scavenge counters that are incorrectly initialized by the
* JVM when UseAdaptiveSizePolicy is set. This bug couldn't be fixed for 1.4.2 FCS due to putback
* restrictions.
*/
private void kludgeMantis(Map<String, Monitor> map, StringMonitor args) {
/*
* the HotSpot 1.4.2 JVM with the +UseParallelGC option along
* with its default +UseAdaptiveSizePolicy option has a bug with
* the initialization of the sizes of the eden and survivor spaces.
* See bugid 4890736.
*
* note - use explicit 1.4.2 counter names here - don't update
* to latest counter names or attempt to find aliases.
*/
String cname = "hotspot.gc.collector.0.name";
StringMonitor collector = (StringMonitor) map.get(cname);
if (collector.stringValue().compareTo("PSScavenge") == 0) {
boolean adaptiveSizePolicy = true;
/*
* HotSpot processes the -XX:Flags/.hotspotrc arguments prior to
* processing the command line arguments. This allows the command
* line arguments to override any defaults set in .hotspotrc
*/
cname = "hotspot.vm.flags";
StringMonitor flags = (StringMonitor) map.get(cname);
String allArgs = flags.stringValue() + " " + args.stringValue();
/*
* ignore the -XX: prefix as it only applies to the arguments
* passed from the command line (i.e. the invocation api).
* arguments passed through .hotspotrc omit the -XX: prefix.
*/
int ahi = allArgs.lastIndexOf("+AggressiveHeap");
int aspi = allArgs.lastIndexOf("-UseAdaptiveSizePolicy");
if (ahi != -1) {
/*
* +AggressiveHeap was set, check if -UseAdaptiveSizePolicy
* is set after +AggressiveHeap.
*/
//
if ((aspi != -1) && (aspi > ahi)) {
adaptiveSizePolicy = false;
}
} else {
/*
* +AggressiveHeap not set, must be +UseParallelGC. The
* relative position of -UseAdaptiveSizePolicy is not
* important in this case, as it will override the
* UseParallelGC default (+UseAdaptiveSizePolicy) if it
* appears anywhere in the JVM arguments.
*/
if (aspi != -1) {
adaptiveSizePolicy = false;
}
}
if (adaptiveSizePolicy) {
// adjust the buggy AdaptiveSizePolicy size counters.
// first remove the real counters.
String eden_size = "hotspot.gc.generation.0.space.0.size";
String s0_size = "hotspot.gc.generation.0.space.1.size";
String s1_size = "hotspot.gc.generation.0.space.2.size";
map.remove(eden_size);
map.remove(s0_size);
map.remove(s1_size);
// get the maximum new generation size
String new_max_name = "hotspot.gc.generation.0.capacity.max";
LongMonitor new_max = (LongMonitor) map.get(new_max_name);
/*
* replace the real counters with pseudo counters that are
* initialized to to the correct values. The maximum size of
* the eden and survivor spaces are supposed to be:
* max_eden_size = new_size - (2*alignment).
* max_survivor_size = new_size - (2*alignment).
* since we don't know the alignment value used, and because
* of other parallel scavenge bugs that result in oversized
* spaces, we just set the maximum size of each space to the
* full new gen size.
*/
Monitor monitor = null;
LongBuffer lb = LongBuffer.allocate(1);
lb.put(new_max.longValue());
monitor = new PerfLongMonitor(eden_size, Units.BYTES, Variability.CONSTANT, false, lb);
map.put(eden_size, monitor);
monitor = new PerfLongMonitor(s0_size, Units.BYTES, Variability.CONSTANT, false, lb);
map.put(s0_size, monitor);
monitor = new PerfLongMonitor(s1_size, Units.BYTES, Variability.CONSTANT, false, lb);
map.put(s1_size, monitor);
}
}
}