[Twisted-Python] Twisted webserver performance issues

[James Y Knight]

When I last looked into the performance issues, I found that sometimes  
trac appears to block for long periods of time without releasing the  
GIL. That seems to be the core of the performance issues, currently.  
When it's responding normally, it's perfectly snappy. But, sometimes,  
it blocks for 10sec at a time.

My next attempt to improve performance was going to be to run trac in  
subprocesses instead of threads. That would hopefully substantially  
fix the delay problem.

James