profiling fuse-python

I am currently writing a fuse using fuse-python. It's already doing what it should. However, after it's mounted for a few weeks, it's becoming noticeably slow. So I wanted to profile it. I know about a few point where it could be optimized. But these should not be the culprits.

However, fuse-python hangs in an infinite loop (see line 733 and 757 of the fuse source). If I run fuse in debug mode (using the -d switch), it will run in foreground. However, I cannot stop it with SIGINT开发者_开发技巧 nor with CTRL+C (which is anyway the same).

I tried to use the signal module to trap the signal in the main thread. But this does not work either. Interestingly, once I shoot the process down with SIGKILL, I see the KeyboardInterrupt on stdout. Also, after a SIGKILL, the signal handler is executed as expected.

This has repercussions on profiling. As the process never terminates normally, cProfile never gets the chance to save the stats file.

Any ideas?

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Python installs a handler that raises KeyboardInterrupt on SIGINT. If a non-default signal handler is detected when fuse's main is called, it will not replace the handler with its own, which normally calls fuse_session_exit and cleans up. After you've called fuse's main, the KeyboardInterrupt is swallowed by CFUNCTYPE wrappers and you never see them.

Your options are to:

• Send SIGQUIT by pressing Ctrl+\, or any other terminating signal other than SIGINT. However fuse will not exit cleanly.
• Install the default signal handler to SIGINT before calling fuse's main, and restore the original when you're done.

old_handler =signal(SIGINT, SIG_DFL)
# call main
signal(SIGINT, old_handler)

I'd highly recommend you switch to an alternative binding also, fuse-python is terribly messy and difficult to work with. I've had a lot of luck with fusepy, and have submitted a few patches there.

When you're able to terminate your FUSE instance without using uncaught signals, the Python profiler will be able to save the stats as per normal.