I was working the following example from Doug Hellmann tutorial on multiprocessing: import multiprocessing def worker(): """worker function""" print 'Worker' return if __name__ == '__main__': jobs = [] for i in range(5): p = multiprocessing.Process(target=worker) jobs.append(p) p.start() W...
I am attempting to to use python to gain some performance on a task that can be highly parallelized using http://docs.python.org/library/multiprocessing. When looking at their library they say to use chunk size for very long iterables. Now, my iterable is not long, one of the dicts that it contains is huge: ~100000 entries, with tuples ...
I am trying to use python's multiprocessing library to hopefully gain some performance. Specifically I am using its map function. Now, for some reason when I swap it out with its single processed counterpart I don't get any memory leaks over time. But using the multiprocessing version of map causes my memory to go through the roof. For t...
Hi, I am using Django ORM in my python script in a decoupled fashion i.e. it's not running in context of a normal Django Project. I am also using the multi processing module. And different process in turn are making queries. The process ran successfully for an hr and exited with this message "IOError: [Errno 32] Broken pipe" Upon ...
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 ...
I'm trying to generate a uuid for a filename, and I'm also using the multiprocessing module. Unpleasantly, all of my uuids end up exactly the same. Here is a small example: import multiprocessing import uuid def get_uuid( a ): ## Doesn't help to cycle through a bunch. #for i in xrange(10): uuid.uuid4() ## Doesn't help to...
I have a problem with the code below, and with any code that uses the print function in the child processes: I can't see any printed statements, even if I use sys.std[err|out].write('worker') in place of print. This is the code (from the official python documentation): from multiprocessing import Process def f(name): print 'hello'...
Back when I made an 8086 emulator I noticed that there was the LOCK prefix intended for synchonization in a multiprocessor environment. Yet the only multitasking I know of for the x86 arch. involves use of the APIC which didn't come around until either the Pentiums or 486s. Was there any kind of standard for 8086 multitasking or was it...
I know this has been answered before, but it seems that executing the script directly "python filename.py" does not work. I have Python 2.6.2 on SuSE Linux. Code: #!/usr/bin/python # -*- coding: utf-8 -*- from multiprocessing import Pool p = Pool(1) def f(x): return x*x p.map(f, [1, 2, 3]) Command line: > python example.py Proce...
I'm having some issues getting the Pipe.send to work in this code. What I would ultimately like to do is send and receive messages to and from the foreign process while its running in a fork. This is eventually going to be integrated into a pexpect loop for talking to interpreter processes. from multiprocessing import Process, Pipe fro...
I have a number of scripts written in Python 2.6 that can be run arbitrarily. I would like to have a single central script that collects the output and displays it in a single log. Ideally it would satisfy these requirements: Every script sends its messages to the same "receiver" for display. If the receiver is not running when the fi...
Hello everyone, Trying to run a time consuming task from a wxpython GUI. The basic idea is to start the long time task from the GUI (pressing a button) and then, a static text on the dialog should be updated from it. First I tried some threading (http://wiki.wxpython.org/LongRunningTasks and many other resourses seen), and I want to sh...
Hello, I am totally a novice in Multi-Core Programming, but I do know how to program C++. Now, I am looking around for Multi-Core Programming library. I just want to give it a try, just for fun, and right now, I found 3 APIs, but I am not sure which one should I stick with. Right now, I see Boost's MPI, OpenMP and TBB. For anyone who h...
This Question has been asked before: http://stackoverflow.com/questions/2936626/how-to-share-a-dictionary-between-multiple-processes-in-python-without-locking However I have several doubts regarding the program given in the answer: The issue is that the following step isn't atomic d['blah'] += 1 Even with locking the answer provi...
I need a bit of an advice for understanding how this whole procedure work exactly. If I am incorrect in any part described below, please correct me. In a single core CPU, it runs each process in the OS, jumping around from one process to another to utilize the best of itself. A process can also have many threads, in which the CPU core r...
Hi, I am using multiprocessing module, and using pools to start multiple workers. But the file descriptors which are opened at the parent process are closed in the worker processes. I want them to be open..! Is there any way to pass file descriptors to be shared across parent and children? ...
I want to use multithreading to make my script faster... I'm still new to this. The Python doc assumes you already understand threading and what-not. So... I have code that looks like this from itertools import izip from multiprocessing import Pool p = Pool() for i, j in izip(hugeseta, hugesetb): p.apply_async(number_crunching, ...
I want a script to start a new process, such that the new process continues running after the initial script exits. I expected that I could use multiprocessing.Process to start a new process, and set daemon=True so that the main script may exit while the created process continues running. But it seems that the second process is silentl...
I am building a logging-bridge between rabbitmq messages and Django application to store background task state in the database for further investigation/review, also to make it possible to re-publish tasks via the Django admin interface. I guess it's nothing fancy, just a standard Producer-Consumer pattern. Web application publishes to...
Hello, I am trying to understand the advantages of the module Multiprocessing over Threading. I know that Multiprocessing get's around the Global Interpreter Lock, but what other advantages are there, and can threading not do the same thing? ...