> On May 14, 2019, at 8:39 AM, Scott, Barry <barry.sc...@forcepoint.com> wrote: > > On Monday, 13 May 2019 15:26:01 BST Chris Withers wrote: >> Hi All, >> >> On some busy instances of the app I'm working with/on, we see websocket >> connections being dropped due to not ping/ponging in time, I'm fairly >> sure this is as a result of some user-written callbacks blocking the >> reactor for long periods of time (seconds...). >> >> What's the best way to debug a twisted application to find out what's >> blocking the reactor? > > Is the process CPU bound or IO bound? > > If CPU bound then cprofile or the tool Glyph mentioned would help.
The tool I mentioned (vmprof) is not a CPU profiler, and will help with I/O bound tasks as well. cProfile can also tell you about wall clock time, but has other limitations that might not make it suitable for this. -g > This advice is from a Linux perspective. > > If its IO bound the you may be waiting on a blocking operation. > You could use strace on the process to see what its doing. > > As its hung for seconds you could connect gdb to the process and see a python > backtrace using the py-bt command. You are likely to catch the offending code. > > The normal bt command will show you what the last python command it calling. > > You could adding logging to your code to show the time of callback entry and > exit. > > If all else fails patch the twisted code to time callbacks and report the > slow > ones. > > Barry > >> >> cheers, >> >> Chris >> >> _______________________________________________ >> Twisted-Python mailing list >> Twisted-Python@twistedmatrix.com >> https://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python > > > > > _______________________________________________ > Twisted-Python mailing list > Twisted-Python@twistedmatrix.com > https://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python _______________________________________________ Twisted-Python mailing list Twisted-Python@twistedmatrix.com https://twistedmatrix.com/cgi-bin/mailman/listinfo/twisted-python
