I have my JavaFx application that reads data from API on background thread ( or for testing it is preloaded from local storage on application start ) and then it processes and sets data to model that is directly binded on properties in my view. Because processing and setting data to model changes text shown in components, it is called with Platform.runLater(). Normally when it is called it consumes around 2% of CPU, but if i run application for longer time, consumption of CPU on data processing goes higher a little bit(probably data processing is too much for GUI thread). It gets for example around +4% in 1 hour.
However what I see as strange behaviour is that when i lock my Windows and go away for few minutes and then come back, CPU usage on data processing changes from 8% to 17% for example and then stays that high. Does it mean that when Windows screen is locked then GUI thread doesn't run? It seems to me like not and then when it unlocks, GUI thread gets overwhelmed byPlatform.runLater() calls. But when it is not processing data, it consumes 0% of CPU, so i'm really confused.
Does anyone know what could cause this? Does GUI thread really stops working when windows are locked?
EDIT:
I've already found that processing received data is probably too intensive task for UI thread and I'm trying to optimize it (do most of processing on background thread and then just call setting data with Platform.runLater.
Code for background download is really simple PoF at this moment and looks like this:
Thread updateDaemon = new Thread(() -> {
try {
while (true) {
TimeUnit.SECONDS.sleep(5);
processMarketStateData(view.getTable(), data);
}
}
}
catch (InterruptedException e) {
logger.error("Background worker interrupted", e);
}
});
updateDaemon.setDaemon(true);
updateDaemon.start();
In processMarketStateData i do some processing and then set data to model on UI thread. But what i'm actually curious about is that strange CPU usage behaviour. When update thread is sleeping and i do not interact with UI then CPU usage is 0%. When processMarketStateData it takes few % of CPU and then it is again 0% till update thread ends its sleep. But for some strange reason after several processMarketStateData calls CPU usage goes up more and more. I goes up by small percentage, like 1% after 50 calls, maybe more. Even weirder is it takes way less calls to produce this strange behaviour when windows screen is locked. When it goes really insane and it takes already around 20% of CPU for call, it goes that high only on processMarketStateData call, for rest of the time it is 0%. After really long ( few hours ) test i ended up in state where application took 25% of CPU permanently and UI was inresponsive. Note that there are 2 these threads running at same time.
My actual question is not "why my ui lags when i process data", that was not hard to find, but it is "why it acts the way it does?" I hope this edit made my question better.
EDIT2: Another strange behaviour as well is that if I leave application minimalized for a while with auto updating and open it then, it is black window for a while, but application that doesn't have auto update is ok. This really makes me think that javaFX UI thread doesn't run when application is minimalized or windows screen is locked. Sadly i could not find much about this.
