So I just finished watching this talk on the Python Global Interpreter Lock (GIL) http://blip.tv/file/2232410. The gist of it is that the GIL is a pretty good design for single core systems (Python essentially leaves the thread handling/scheduling up to the operating system). But that this can seriously backfire on multi-core systems an...
I'm hoping someone can provide some insight as to what's fundamentally different about the Java Virtual Machine that allows it to implement threads nicely without the need for a Global Interpreter Lock (GIL), while Python necessitates such an evil. ...
Does anybody knows fate of Global Interpreter Lock in Python 3.1 against C++ multithreading integration ...
What is a global interpreter lock and why is that an issue? A lot noise has been made around removing the GIL from Python, and I'd like to understand why that is so important. I never wrote a compiler nor an interpreter myself, so don't be frugal with details, I'll probably need them to understand. ...
Hi, I've got a library written in C++ which I wrap using SWIG and use in python. Generally there is one class with few methods. The problem is that calling these methods may be time consuming - they may hang my application (GIL is not released when calling these methods). So my question is: what is the simplest way to release GIL for t...
I often see people talking that the GIL is per Python Interpreter (even here on stackoverflow). But what I see in the source code it seems to be that the GIL is a global variable and therefore there is one GIL for all Interpreters in each python process. I know they did this because there is no interpreter object passed around like lua ...
Hi friends, Does the presence of python GIL imply that in python multi threading the same operation is not so different from repeating it in a single thread?. For example, If I need to upload two files, what is the advantage of doing them in two threads instead of uploading them one after another?. I tried a big math operation in bot...
I just saw this section of Unladen Swallow's documentation come up on Hacker News. Basically, it's the Google engineers saying that they're not optimistic about removing the GIL. However, it seems as though there is discussion about the garbage collector interspersed with this talk about the GIL. Could someone explain the relation to ...
I was reading this page on the new GIL found/to be found in Python 3.2 and I was wondering if it is the "killer feature" that will trigger a transition from Python 2.x to 3.x. What do you guys think? ...
The simplest way to manipulate the GIL in Python C extensions is to use the macros provided: my_awesome_C_function() { blah; Py_BEGIN_ALLOW_THREADS // do stuff that doesn't need the GIL if (should_i_call_back) { Py_BLOCK_THREADS // do stuff that needs the GIL Py_UNBLOCK_THREADS } Py_E...
In python, I have a global variable defined that gets read/incremented by different threads. Because of the GIL, will this ever cause problems without using any kind of locking mechanism? ...
I want to use Python's multiprocessing to do concurrent processing without using locks (locks to me are the opposite of multiprocessing) because I want to build up multiple reports from different resources at the exact same time during a web request (normally takes about 3 seconds but with multiprocessing I can do it in .5 seconds). My ...
Some discussion in another question has encouraged me to to better understand cases where locking is required in multithreaded Python programs. Per this article on threading in Python, I have several solid, testable examples of pitfalls that can occur when multiple threads access shared state. The example race condition provided on thi...
Hello all, my problem is the GIL of course. While I'm analysing data it would be nice to present some plots in between (so it's not too boring waiting for results) But the GIL prevents this (and this is bringing me to the point of asking myself if Python was such a good idea in the first place). I can only display the plot, wait till ...
Suppose I have a C(++) function taking an integer, and it is bound to (C)python with python api, so I can call it from python: import c_module c_module.f(10) now, I want to parallelize it. The problem is: how does the GIL work in this case? Suppose I have a queue of numbers to be processed, and some workers (threading.Thread) working ...
Was looking to write a little web crawler in python. I was starting to investigate writing it as a multithreaded script, one pool of threads downloading and one pool processing results. Due to the GIL would it actually do simultaneous downloading? How does the GIL affect a web crawler? Would each thread pick some data off the socket, the...
Why is it that you can run Jython and IronPython without the need for a GIL but Python (CPython) requires a GIL? ...
Are there any languages which feature static type checking like in C++ with modern syntax like in Python, and does not have GIL? I belive, Python 3 with ability to explicitly declare type of each variable would be 'almost there', but GIL makes me sad. Java is nice, but I need something more 'embedable' without bulky JRE. Update: Anyth...
I'm just starting to work on a tornado application that is having some CPU issues. The CPU time will monotonically grow as time goes by, maxing out the CPU at 100%. The system is currently designed to not block the main thread. If it needs to do something that blocks and asynchronous drivers aren't available, it will spawn another thr...
In the current implementation of CPython, there is an object known as the "GIL" or "Global Interpreter Lock". It is essentially a mutex that prevents two Python threads from executing Python code at the same time. This prevents two threads from being able to corrupt the state of the Python interpreter, but also prevents multiple threads ...