Multithreaded Telnet sessions

[Pierre-Frédéric Caillaud]

> I can't get over how much faster it is to push a change to 800+
> routers using 20+ threads!

	yes ? and the more ping time you have, the more you can gain by thread  
parallelism.

> Anything over 20 threads seems to take processor utilization to 100%.
> Is there any benefit to starting additional threads once the CPU is at
> 100% ?

	Probably not. With few threads your app is network-lag-limited. With too  
many threads it becomes cpu-limited and might even get slower. I have  
noticed that multithreading network code in Python gives up at a rather  
low number of threads, in the 20-50 as you noticed, which worries me  
because the OS can do a lot better than that. Perhaps is this simply that  
python with 1/20 of your CPU is too slow ? If you want to have 100 threads  
you'll have to spend a few days coding it in (argh) C++ or (argh) Java.

	Or if your brain doesn't explode, you can code it using asynchronous  
select and the asynchat module...

	Or just be happy that it's 20 times faster than before...