How to limit JProfiler to a subtree - jprofiler

I have a method called com.acmesoftware.shared.AbstractDerrivedBean.getDerivedUniqueId(). When I JProfiler the application, this method, getDerivedUniqueId(), is essentially buried 80 methods deep as expected. The method is invoked on behalf of every bean in the application. I'm trying to record CPU calltree starting with this method down to leaf node (ie, one of the excluded classes).
I tried the following but it didn't produce the expected outcome:
Find a method above the method targeted for profiling, eg, markForDeletion().
set trigger to start recording at getDerivedUniqueId()
set trigger to STOP recording at markForDeletion()
I was expecting to only see everything below markForDeletion(), but I saw everything up to but not INCLUDING getDerivedUniqueId(), which is the opposite of my intended goal. Worse yet, even with 5ms sampling, this trigger increased the previous running time from 10 minutes to "I terminated after 3 hours of running". It seems the trigger is adding a giant amount of overhead on top of the overhead. Hence, even if I figure out how to correctly enable the trigger, the added overhead would seem to render it ineffective.
The reason I need to limit the recording to just this method is: When running in 5ms sampling mode, the application completes in 10 minutes. When I run it in full instrumentation, I've waited 3 hours and it still hasn't completed. Hence, I need to turn on full instrumentation ONLY after getDerivedUniqueId() is invoked and pause profiling when getDerivedUniqueId() is exited.
-- Updated/Edit:
Thank you Ingo Kegel for your assistance.
I am likely not clear on how to use triggers. In the code below, I set triggers as shown after the code. My expectation is that when I JProfile the application (both sampling and full instrumentation) with the below configured triggers, if boolean isCollectMetrics is false, I should see 100% or 99.9% of cpu in filtered classes. However, that is not the case. The CPU tree seems not to take into account the triggers.
Secondly, when isCollectMetrics is true, the jprofiler call tree I expect would start with startProfiling() and end at stopProfiling(). Again, this is not the case either.
The method contains() is the bottleneck. It eventually calls one of 150 getDerivedUniqueId(). I am trying to pinpoint which getDerivedUniqueId() is causing the performance degradation.
public static final AtomicLong doEqualContentTime = new AtomicLong();
public static final AtomicLong instCount = new AtomicLong();
protected boolean contentsEqual(final InstanceSetValue that) {
if (isCollectMetrics) {
// initialization code removed for clarity
// ..........
// ..........
final Set<Instance> c1 = getReferences();
final Set<Instance> c2 = that.getReferences();
long st = startProfiling(); /// <------- start here
for (final Instance inst : c1) {
instCount.incrementAndGet();
if (!c2.contains(inst)) {
long et = stopProfiling(); /// <------- stop here
doEqualContentTime.addAndGet(et - st);
return false;
}
}
long et = stopProfiling(); /// <------- stop here
doEqualContentTime.addAndGet(et - st);
return true;
} else {
// same code path as above but w/o the profiling. code removed for bravity.
// ......
// ......
return true;
}
}
public long startProfiling() {
return System.nanoTime();
}
public long stopProfiling() {
return System.nanoTime();
}
public static void reset() {
doEqualContentTime.set(0);
instCount.set(0);
}
The enabled triggers:
startProfiling trigger:
stopProfiling trigger:
I've tried 'Start Recordings' or 'Record CPU' buttons separately to capture the call tree only

If the overhead with instrumentation is large, you should refine your filters. With good filters, the instrumentation overhead can be very small,
As for the trigger setup, the correct actions are:
"Start recording" with CPU data selected
"Wait for the event to finish"
"Stop recording" with CPU data selected

Related

Is this the correct way to stop a function and restart it with new data?

I have a function which does a bunch of searching and setting fields. Now, I want it to stop doing that and restart as soon as I change anything, is this the correct way of doing that?
The plan is that I don't have work being done that is no longer used, and that slower updates don't finish after a more recent, faster update
private var autoUpdateJob: Job = Job()
(...)
// Something happens (eg. an onTextChangedListener in an EditText gets triggered)
launch {
autoUpdateJob.cancelAndJoin()
autoUpdateJob = launch { flight = autoValues() }
}

Optaplanner: NullPointerException when calling scoreDirector.beforeVariableChanged in a simple custom move

I am building a Capacited Vehicle Routing Problem with Time Windows, but with one small difference when compared to the one provided in examples from the documentation: I don't have a depot. Instead, each order has a pickup step, and a delivery step, in two different locations.
(like in the Vehicle Routing example from the documentation, the previousStep planning variable has the CHAINED graph type, and its valueRangeProviderRefs includes both Drivers, and Steps)
This difference adds a couple of constraints:
the pickup and delivery steps of a given order must be handled by the same driver
the pickup must be before the delivery
After experimenting with constraints, I have found that it would be more efficient to implement two types of custom moves:
assign both steps of an order to a driver
rearrange the steps of a driver
I am currently implementing that first custom move. My solver's configuration looks like this:
SolverFactory<RoutingProblem> solverFactory = SolverFactory.create(
new SolverConfig()
.withSolutionClass(RoutingProblem.class)
.withEntityClasses(Step.class, StepList.class)
.withScoreDirectorFactory(new ScoreDirectorFactoryConfig()
.withConstraintProviderClass(Constraints.class)
)
.withTerminationConfig(new TerminationConfig()
.withSecondsSpentLimit(60L)
)
.withPhaseList(List.of(
new LocalSearchPhaseConfig()
.withMoveSelectorConfig(CustomMoveListFactory.getConfig())
))
);
My CustomMoveListFactory looks like this (I plan on migrating it to an MoveIteratorFactory later, but for the moment, this is easier to read and write):
public class CustomMoveListFactory implements MoveListFactory<RoutingProblem> {
public static MoveListFactoryConfig getConfig() {
MoveListFactoryConfig result = new MoveListFactoryConfig();
result.setMoveListFactoryClass(CustomMoveListFactory.class);
return result;
}
#Override
public List<? extends Move<RoutingProblem>> createMoveList(RoutingProblem routingProblem) {
List<Move<RoutingProblem>> moves = new ArrayList<>();
// 1. Assign moves
for (Order order : routingProblem.getOrders()) {
Driver currentDriver = order.getDriver();
for (Driver driver : routingProblem.getDrivers()) {
if (!driver.equals(currentDriver)) {
moves.add(new AssignMove(order, driver));
}
}
}
// 2. Rearrange moves
// TODO
return moves;
}
}
And finally, the move itself looks like this (nevermind the undo or the isDoable for the moment):
#Override
protected void doMoveOnGenuineVariables(ScoreDirector<RoutingProblem> scoreDirector) {
assignStep(scoreDirector, order.getPickupStep());
assignStep(scoreDirector, order.getDeliveryStep());
}
private void assignStep(ScoreDirector<RoutingProblem> scoreDirector, Step step) {
StepList beforeStep = step.getPreviousStep();
Step afterStep = step.getNextStep();
// 1. Insert step at the end of the driver's step list
StepList lastStep = driver.getLastStep();
scoreDirector.beforeVariableChanged(step, "previousStep"); // NullPointerException here
step.setPreviousStep(lastStep);
scoreDirector.afterVariableChanged(step, "previousStep");
// 2. Remove step from current chained list
if (afterStep != null) {
scoreDirector.beforeVariableChanged(afterStep, "previousStep");
afterStep.setPreviousStep(beforeStep);
scoreDirector.afterVariableChanged(afterStep, "previousStep");
}
}
The idea being that at no point I'm doing an invalid chained list manipulation:
However, as the title and the code comment indicate, I am getting a NullPointerException when I call scoreDirector.beforeVariableChanged. None of my variables are null (I've printed them to make sure). The NullPointerException doesn't occur in my code, but deep inside Optaplanner's inner workings, making it difficult for me to fix it:
Exception in thread "main" java.lang.NullPointerException
at org.drools.core.common.NamedEntryPoint.update(NamedEntryPoint.java:353)
at org.drools.core.common.NamedEntryPoint.update(NamedEntryPoint.java:338)
at org.drools.core.impl.StatefulKnowledgeSessionImpl.update(StatefulKnowledgeSessionImpl.java:1579)
at org.drools.core.impl.StatefulKnowledgeSessionImpl.update(StatefulKnowledgeSessionImpl.java:1551)
at org.optaplanner.core.impl.score.stream.drools.DroolsConstraintSession.update(DroolsConstraintSession.java:49)
at org.optaplanner.core.impl.score.director.stream.ConstraintStreamScoreDirector.afterVariableChanged(ConstraintStreamScoreDirector.java:137)
at org.optaplanner.core.impl.domain.variable.inverserelation.SingletonInverseVariableListener.retract(SingletonInverseVariableListener.java:96)
at org.optaplanner.core.impl.domain.variable.inverserelation.SingletonInverseVariableListener.beforeVariableChanged(SingletonInverseVariableListener.java:46)
at org.optaplanner.core.impl.domain.variable.listener.support.VariableListenerSupport.beforeVariableChanged(VariableListenerSupport.java:170)
at org.optaplanner.core.impl.score.director.AbstractScoreDirector.beforeVariableChanged(AbstractScoreDirector.java:430)
at org.optaplanner.core.impl.score.director.AbstractScoreDirector.beforeVariableChanged(AbstractScoreDirector.java:390)
at test.optaplanner.solver.AssignMove.assignStep(AssignMove.java:98)
at test.optaplanner.solver.AssignMove.doMoveOnGenuineVariables(AssignMove.java:85)
at org.optaplanner.core.impl.heuristic.move.AbstractMove.doMove(AbstractMove.java:35)
at org.optaplanner.core.impl.heuristic.move.AbstractMove.doMove(AbstractMove.java:30)
at org.optaplanner.core.impl.score.director.AbstractScoreDirector.doAndProcessMove(AbstractScoreDirector.java:187)
at org.optaplanner.core.impl.localsearch.decider.LocalSearchDecider.doMove(LocalSearchDecider.java:132)
at org.optaplanner.core.impl.localsearch.decider.LocalSearchDecider.decideNextStep(LocalSearchDecider.java:116)
at org.optaplanner.core.impl.localsearch.DefaultLocalSearchPhase.solve(DefaultLocalSearchPhase.java:70)
at org.optaplanner.core.impl.solver.AbstractSolver.runPhases(AbstractSolver.java:98)
at org.optaplanner.core.impl.solver.DefaultSolver.solve(DefaultSolver.java:189)
at test.optaplanner.OptaPlannerService.testOptaplanner(OptaPlannerService.java:68)
at test.optaplanner.App.main(App.java:13)
Is there something I did wrong? It seems I am following the documentation for custom moves fairly closely, outside of the fact that I am using exclusively java code instead of drools.
The initial solution I feed to the solver has all of the steps assigned to a single driver. There are 15 drivers and 40 orders.
In order to bypass this error, I have tried a number of different things:
remove the shadow variable annotation, turn Driver into a problem fact, and handle the nextStep field myself => this makes no difference
use Simulated Annealing + First Fit Decreasing construction heuristics, and start with steps not assigned to any driver (this was inspired by looking up the example here, which is more complete than the one from the documentation) => the NullPointerException appears on afterVariableChanged instead, but it still appears.
a number of other things which were probably not very smart
But without a more helpful error message, I can't think of anything else to try.
Thank you for your help

Custom command to go back in a process instance (execution)

I have a process where I have 3 sequential user tasks (something like Task 1 -> Task 2 -> Task 3). So, to validate the Task 3, I have to validate the Task 1, then the Task 2.
My goal is to implement a workaround to go back in an execution of a process instance thanks to a Command like suggested in this link. The problem is I started to implement the command by it does not work as I want. The algorithm should be something like:
Retrieve the task with the passed id
Get the process instance of this task
Get the historic tasks of the process instance
From the list of the historic tasks, deduce the previous one
Create a new task from the previous historic task
Make the execution to point to this new task
Maybe clean the task pointed before the update
So, the code of my command is like that:
public class MoveTokenCmd implements Command<Void> {
protected String fromTaskId = "20918";
public MoveTokenCmd() {
}
public Void execute(CommandContext commandContext) {
HistoricTaskInstanceEntity currentUserTaskEntity = commandContext.getHistoricTaskInstanceEntityManager()
.findHistoricTaskInstanceById(fromTaskId);
ExecutionEntity currentExecution = commandContext.getExecutionEntityManager()
.findExecutionById(currentUserTaskEntity.getExecutionId());
// Get process Instance
HistoricProcessInstanceEntity historicProcessInstanceEntity = commandContext
.getHistoricProcessInstanceEntityManager()
.findHistoricProcessInstance(currentUserTaskEntity.getProcessInstanceId());
HistoricTaskInstanceQueryImpl historicTaskInstanceQuery = new HistoricTaskInstanceQueryImpl();
historicTaskInstanceQuery.processInstanceId(historicProcessInstanceEntity.getId()).orderByExecutionId().desc();
List<HistoricTaskInstance> historicTaskInstances = commandContext.getHistoricTaskInstanceEntityManager()
.findHistoricTaskInstancesByQueryCriteria(historicTaskInstanceQuery);
int index = 0;
for (HistoricTaskInstance historicTaskInstance : historicTaskInstances) {
if (historicTaskInstance.getId().equals(currentUserTaskEntity.getId())) {
break;
}
index++;
}
if (index > 0) {
HistoricTaskInstance previousTask = historicTaskInstances.get(index - 1);
TaskEntity newTaskEntity = createTaskFromHistoricTask(previousTask, commandContext);
currentExecution.addTask(newTaskEntity);
commandContext.getTaskEntityManager().insert(newTaskEntity);
AtomicOperation.TRANSITION_CREATE_SCOPE.execute(currentExecution);
} else {
// TODO: find the last task of the previous process instance
}
// To overcome the "Task cannot be deleted because is part of a running
// process"
TaskEntity currentUserTask = commandContext.getTaskEntityManager().findTaskById(fromTaskId);
if (currentUserTask != null) {
currentUserTask.setExecutionId(null);
commandContext.getTaskEntityManager().deleteTask(currentUserTask, "jumped to another task", true);
}
return null;
}
private TaskEntity createTaskFromHistoricTask(HistoricTaskInstance historicTaskInstance,
CommandContext commandContext) {
TaskEntity newTaskEntity = new TaskEntity();
newTaskEntity.setProcessDefinitionId(historicTaskInstance.getProcessDefinitionId());
newTaskEntity.setName(historicTaskInstance.getName());
newTaskEntity.setTaskDefinitionKey(historicTaskInstance.getTaskDefinitionKey());
newTaskEntity.setProcessInstanceId(historicTaskInstance.getExecutionId());
newTaskEntity.setExecutionId(historicTaskInstance.getExecutionId());
return newTaskEntity;
}
}
But the problem is I can see my task is created, but the execution does not point to it but to the current one.
I had the idea to use the activity (via the object ActivityImpl) to set it to the execution but I don't know how to retrieve the activity of my new task.
Can someone help me, please?
Unless somethign has changed in the engine significantly the code in the link you reference should still work (I have used it on a number of projects).
That said, when scanning your code I don't see the most important command.
Once you have the current execution, you can move the token by setting the current activity.
Like I said, the code in the referenced article used to work and still should.
Greg
Referring the same link in your question, i would personally recommend to work with the design of you your process. use an exclusive gateway to decide whether the process should end or should be returned to the previous task. if the generation of task is dynamic, you can point to the same task and delete local variable. Activiti has constructs to save your time from implementing the same :).

Asynchronously start only one Task to process a static Queue, stopping when it's done

Basically I have a static custom queue of objects I want to process. From multiple threads, I need to kick off a singular Task that will process the queued objects, stopping the task when all items are dequeued.
Some psuedo code:
static CustomQueue _customqueue;
static Task _processQueuedItems;
public static void EnqueueSomething(object something) {
_customqueue.Enqueue(something);
StartProcessingQueue();
}
static void StartProcessingQueue() {
if(_processQueuedItems != null) {
_processQueuedItems = new Task(() => {
while(_customqueue.Any()) {
var stuffToDequeue = _customqueue.Dequeue();
/* do stuff */
}
});
_processQueuedItems.Start();
}
if(_processQueuedItems.Status != TaskStatus.Running) {
_processQueuedItems.Start();
}
}
If it makes a difference my custom queue is a queue that essentially holds items until they reach a certain age, then allows them to dequeue. Everytime an item is touched its timer starts again. I know this piece works fine.
The part I'm struggling with is the parallelism. (Clearly, I don't know what I'm doing here). What I want is to have one thread process the queue until it's complete, then go away. If another call comes in it doesn't start a new thread unless it has to.
I hope that explains my issue okay.
You might want to consider using BlockingCollection<T> here. You could make your custom queue implement IProducerConsumerCollection, in which case BC could use it directly.
You'd then just need to start a long running Task to call blockingCollection.GetConsumingEnumerable() and process the items in a foreach. The task will automatically block when the collection is empty, and restart when a new item is Enqueued.

.NET 4.0 Threading.Tasks

I've recently started working on a new application which will utilize task parallelism. I have just begun writing a tasking framework, but have recently seen a number of posts on SO regarding the new System.Threading.Tasks namespace which may be useful to me (and I would rather use an existing framework than roll my own).
However looking over MSDN I haven't seen how / if, I can implement the functionality which I'm looking for:
Dependency on other tasks completing.
Able to wait on an unknown number of tasks preforming the same action (maybe wrapped in the same task object which is invoked multiple times)
Set maximum concurrent instances of a task since they use a shared resource there is no point running more than one at once
Hint at priority, or scheduler places tasks with lower maximum concurrent instances at a higher priority (so as to keep said resource in use as much as possible)
Edit ability to vary the priority of tasks which are preforming the same action (pretty poor example but, PredictWeather (Tommorrow) will have a higher priority than PredictWeather (NextWeek))
Can someone point me towards an example / tell me how I can achieve this? Cheers.
C# Use Case: (typed in SO so please for give any syntax errors / typos)
**note Do() / DoAfter() shouldn't block the calling thread*
class Application ()
{
Task LeafTask = new Task (LeafWork) {PriorityHint = High, MaxConcurrent = 1};
var Tree = new TaskTree (LeafTask);
Task TraverseTask = new Task (Tree.Traverse);
Task WorkTask = new Task (MoreWork);
Task RunTask = new Task (Run);
Object SharedLeafWorkObject = new Object ();
void Entry ()
{
RunTask.Do ();
RunTask.Join (); // Use this thread for task processing until all invocations of RunTask are complete
}
void Run(){
TraverseTask.Do ();
// Wait for TraverseTask to make sure all leaf tasks are invoked before waiting on them
WorkTask.DoAfter (new [] {TraverseTask, LeafTask});
if (running){
RunTask.DoAfter (WorkTask); // Keep at least one RunTask alive to prevent Join from 'unblocking'
}
else
{
TraverseTask.Join();
WorkTask.Join ();
}
}
void LeafWork (Object leaf){
lock (SharedLeafWorkObject) // Fake a shared resource
{
Thread.Sleep (200); // 'work'
}
}
void MoreWork ()
{
Thread.Sleep (2000); // this one takes a while
}
}
class TaskTreeNode<TItem>
{
Task LeafTask; // = Application::LeafTask
TItem Item;
void Traverse ()
{
if (isLeaf)
{
// LeafTask set in C-Tor or elsewhere
LeafTask.Do(this.Item);
//Edit
//LeafTask.Do(this.Item, this.Depth); // Deeper items get higher priority
return;
}
foreach (var child in this.children)
{
child.Traverse ();
}
}
}
There are numerous examples here:
http://code.msdn.microsoft.com/ParExtSamples
There's a great white paper which covers a lot of the details you mention above here:
"Patterns for Parallel Programming: Understanding and Applying Parallel Patterns with the .NET Framework 4"
http://www.microsoft.com/downloads/details.aspx?FamilyID=86b3d32b-ad26-4bb8-a3ae-c1637026c3ee&displaylang=en
Off the top of my head I think you can do all the things you list in your question.
Dependencies etc: Task.WaitAll(Task[] tasks)
Scheduler: The library supports numerous options for limiting number of threads in use and supports providing your own scheduler. I would avoid altering the priority of threads if at all possible. This is likely to have negative impact on the scheduler, unless you provide your own.