Using C++ Object to test QML Garbage Collection

[wade-J]

In my mobile game , I use QML. The performance is not stable and I am wondering whether the reason is garbage collection.
Since I haven't found way to know when the QML does Garbage Collection, I used such way:

I register a C++ type into QML , and create an instance in my JavaScript code. The C++ type is different in two points:

(1)In constructor, QQmlEngine::setObjectOwnership(this,QQmlEngine::JavaScriptOwnership);
(2)In destructor, emit gcSignal();

So, eveytime QML does garbage collection, the instance will be destructed, and I can receive the gcSignal().

Is this a useful way?
Is there any other way to help?

[t3685]

That's one way of doing it. The problem for you would be to connect every object to make to a listeren of your gc signal.

Before you go deeper into garbage collection, have you profiled the application with the qml profiler?

[wade-J]

The phenomenon is that my game lags periodically. It is not obvious , but I can feel it. So I doubt it is of gc reason.

I just use one object,I call it "ghost", to listen of the gc signal, and everytime gc happens, the ghost will destructed, and a new ghost will be created.

If I thought it were right,I could receive the signal. And it works as I thought. What is weird is that I can not receive the signal if I add some irrelated code such as just add one line:var x = new Date(),when re-create the ghost. So confused.

Yes , I profiled the application before.