1.8.5 / high CPU load

[ghollf]

IDE has permanently high CPU load after startup.

procexp shows for javaw permanently executing a thread with higher load...

Start Address:
msvcr100.dll!_endthreadex+0x6a
Stack:
listSerialsj.dll!sp_get_lib_version_string+0x74f
  SETUPAPI.dll!SetupDiGetClassDevsA+0x3d
    SETUPAPI.dll!SetupDiGetClassDevsExW+<changing>
      ...

[facchinm]

Hi @ghollf ,
this seems related with the JNI wrapper over liblistSerials. Are you able to see the serial ports list? Does it get populated?
sp_get_lib_version_string API doesn't get explicitly called by the IDE, it's quite strange it appears in your stacktrace.

[ghollf]

Yes, Tools>Port lists 15 ports (mostly from USB devices like mobiles or 3G modems).

[facchinm]

Probably the high cpu usage is cause by the huge number of devices (and thus syscalls to retrieve the information).
When libusb/libusb#86 will be completed we'll be able to switch to an event-based serial listing.

[ghollf]

Updated initial post. Also ports are listed immediately. Nearly all ports are associated to disconnected devices. Running listSerialC doesn't show any strange behaviour.

[trogper]

I have found a way to reproduce the bug:
quickly toggle focus to the main IDE window a few times, the cpu usage goes high,
give focus to serial monitor and the usage goes down again

[AlexGuo1998]

Hi, @facchinm
It seems that this issue is caused by unconnected (or disconnected) serial ports.
For example (v1.8.5, on Windows 10), plug in your Arduino board and open serial monitor, then unplug the board. Wait a moment, and you'll notice a high CPU load.

[facchinm]

@AlexGuo1998 I've been able to reproduce it, thanks! I'll let you know as soon as there's a patch available to be tested.

[trogper]

@AlexGuo1998, @facchinm
For me, the high CPU usage does occur when no board is connected and also when it still is connected.
I have tried to profile the IDE with visualVM, but have only found out it's BatikCleaner Thread

[facchinm]

The serial monitor issue gets solved by #8046 , @trogper 's problem looks more like the java u171 issue (#8009)

[trogper]

@facchinm so I updated Java and the usage bug when switching focus disappeared. I have since had high CPU usage, it seemed to be related to serial monitor. I have not tried to reproduce it