I Would like to move some jobs to another QThread to avoid the frozen of the main thread (GUI). I tried python ThreadPoolExecutor to create a thread. However, the child thread is too slow. According to the suggestion of multithreading-in-extension , I tried QTimer. It also frozen GUI. Now I am tryi…

Python multi-threading is really messy in general and it is further complicated by using a Python interpreter embedded in an application. I would recommend running background processing in a Python CLI module (which runs processing in a separate process) or implement it in a C++ loadable module (wh…

you can do the following: def onListenButton(self): self.worker = Worker() original_stdin = sys.stdin # Unlock SlicerPython GIL sys.stdin = open(os.devnull) try: self.thread_pool.start(self.worker) except Exception as e: # Is something wrong …

[image] Alex_Vergara: original_stdin = sys.stdin # Unlock SlicerPython GIL Do you know what are the side effects of this?

yep, if you try to do this more than once slicer crashes, but if you wait until the end it works pretty well. So you shall enforce some kind of lock yourself. Oh, and this only works with python3, I forgot to mention this.

To elaborate more on this: SlicerPython is attached to the console which is locked by slicer itself, this procedure liberates temporarily the console input and sets a virtual input with no owner (no GIL). If you try to use slicer console while it is calculating, then SlycerPython will not read from …

Thank you very much. I just tried the new code of onListenButton function. I got the new errors as the following" Received signal 11 SEGV_MAPERR 0000000000a0 #0 0x7f7f1721558f #1 0x7f7f15c4785d #2 0x7f7f17215a9e #3 0x7f7f00d6f890 #4 0x7f7f0c259d70 tupledealloc #5 0x7f7f0c2473c6 _PyCFunct…

instead of using terminate and join, try using quit and wait respectively as they are the recommended with QThreadPool. Anyways, if you want to try the multiprocessing module from multiprocessing import Pool def worker_wrapper(args): worker = Worker(*args) return worker.run() original_st…

[image] Alex_Vergara: To elaborate more on this: SlicerPython is attached to the console which is locked by slicer itself, this procedure liberates temporarily the console input and sets a virtual input with no owner (no GIL). If you try to use slicer console while it is calculating, then Slycer…

Thank you very much! After I try it and get back to you.

Slicer crashes when using QThreadPool to start QRunnable in python module

Support

jamesobutler (James Butler) September 30, 2019, 6:51pm 12

We previously had a discussion (Running multiple CLIs at once) about this, but didn’t take any action yet.

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Slicer crashes when using QThreadPool to start QRunnable in python module

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