Quite some numpy routines release GIL, so they can be efficiently parallel in threads (info). Maybe you don’t need to do anything special! You can use this question to find whether the routines you need are among the ones that release GIL. In short, search for ALLOW_THREADS or nogil in the source. (Also note that … Read more
You can think of greenlets more like cooperative threads. What this means is that there is no scheduler pre-emptively switching between your threads at any given moment – instead your greenlets voluntarily/explicitly give up control to one another at specified points in your code. Does the GIL affect them? Can there be more than one … Read more
Python (the language) doesn’t need a GIL (which is why it can perfectly be implemented on JVM [Jython] and .NET [IronPython], and those implementations multithread freely). CPython (the popular implementation) has always used a GIL for ease of coding (esp. the coding of the garbage collection mechanisms) and of integration of non-thread-safe C-coded libraries (there … Read more
Python’s GIL is intended to serialize access to interpreter internals from different threads. On multi-core systems, it means that multiple threads can’t effectively make use of multiple cores. (If the GIL didn’t lead to this problem, most people wouldn’t care about the GIL – it’s only being raised as an issue because of the increasing … Read more