On 3/18/09, [email protected] <[email protected]> wrote: > Hi all, > I have a question this week about thread priority, the little python > application I am writing is CPU bound (on my crappy old machine). > > I have split the application into threads (using threading) which appears > to work OK, but the application is still responding at the speed of the > slowest thread. > > The app is a video processing/display, I have: > -- > Main Thread: pyGTK display/buttons. > Capture Thread: grab from V4L2 and render onto display. > Process Thread: grab image from Capture thread and process, processing is > done using a wrapper to C library. > -- > > The video display framerate drops to that of the processing thread and the > CPU is pegged at 100%. If I disable the processing thread then the video > is smooth, with the correct framerate and CPU is mostly idle. > > If I put a large sleep (5s for example) in the processing thread I get > slow video (whilst processing) and then smooth video (whilst sleeping), so > I believe that I have done the threading correctly. > > So my questions are: > Is there a way to lower the priority of the 'Process Thread' so that it > does not run as intensively? > Or, is there a way to increase the rate at which the 'Process Thread' is > swapped out and thus allowing the other (less intensive) threads to get > CPU time? > > Cheers, > Simon.
If possible, I would suggest trying to use the Popen2 module. This way, you should be able to re-nice it (os.nice) after the fork. This may be easy or painful depending on how much the thread needs to talk to it's parent. -Mark C. _______________________________________________ clug-talk mailing list [email protected] http://clug.ca/mailman/listinfo/clug-talk_clug.ca Mailing List Guidelines (http://clug.ca/ml_guidelines.php) **Please remove these lines when replying
