** Description changed: - When creating a child process from a python script that uses pygtk 2.21, - such subprocess.check_call(), 100% of the CPU is used (technically, - 100% of the core the python interpreter is using). + == Impact == + + pygtk apps which handle signals busy-loop in the glib main loop + dispatch, causing 100% CPU usage after a signal is received. This + commonly occurs when spawned child processes exit. + + == TEST CASE == + + A simple testcase (pygtk-signal-testcase.py) is attached. To trigger + the bug, run the testcase and send the process SIGCHLD. When run with + pygtk 2.22-0ubuntu1 the test process will now consume 100% CPU. + + == Regression Potential == + + PyGTK is core infrastructure, so the potential impact of a regression is + high. However, the patch is small and clearly correct, and the file + descriptor being read from is nonblocking, so it should not cause + application hangs even if it tries to read more bytes than are there. + + + Original bugreport follows: + When creating a child process from a python script that uses pygtk 2.21, such subprocess.check_call(), 100% of the CPU is used (technically, 100% of the core the python interpreter is using). If the creation of the child processes are removed, the script runs as expected. According to user exarkun on the #python IRC channel, the problem may be manifesting when the child process exits. It may be related to a bug that was fixed in 9.10, but broken in 9.04. If that is the case, this is the relevant bug report: https://bugzilla.gnome.org/show_bug.cgi?id=481569 The code in which I noticed this problem is in the videometadata.py module of Rapid Photo Downloader: http://bazaar.launchpad.net/~dlynch3/rapid/trunk/annotate/head%3A/rapid/videometadata.py#L189 ProblemType: Bug DistroRelease: Ubuntu 10.10 Package: python-gtk2 2.21.0-0ubuntu1 ProcVersionSignature: Ubuntu 2.6.35-22.35-generic 2.6.35.4 Uname: Linux 2.6.35-22-generic x86_64 Architecture: amd64 Date: Thu Oct 21 22:51:42 2010 InstallationMedia: Ubuntu 10.10 "Maverick Meerkat" - Release amd64 (20101007) ProcEnviron: - PATH=(custom, user) - LANG=en_US.utf8 - SHELL=/bin/bash + PATH=(custom, user) + LANG=en_US.utf8 + SHELL=/bin/bash SourcePackage: pygtk
** Attachment added: "Simple testcase" https://bugs.launchpad.net/ubuntu/+source/pygtk/+bug/664920/+attachment/2089709/+files/pygtk-signal-testcase.py -- You received this bug notification because you are a member of Ubuntu Desktop Bugs, which is subscribed to pygtk in Ubuntu. https://bugs.launchpad.net/bugs/664920 Title: SRU: 100% CPU usage when calling a child process from a python script -- desktop-bugs mailing list desktop-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/desktop-bugs
