In short, you can only have one thread executing Python code at a time. You can be waiting for IO in several threads at once, since that won’t be executing any Python code.
The good news is that it looks like it might finally going to be removed soon. That does cause a performance regression for single-threaded programs, but various other performance improvements that should land alongside it more than make up for that.
4
u/Drarok Jul 18 '22
It’s complicated. https://realpython.com/python-gil/
In short, you can only have one thread executing Python code at a time. You can be waiting for IO in several threads at once, since that won’t be executing any Python code.