What's the cost of using hundreds of threads?

[Przemysław Różycki]

Hello,

I have written some code, which creates many threads for each connection 
('main connection'). The purpose of this code is to balance the load 
between several connections ('pipes'). The number of spawned threads 
depends on how many pipes I create (= 2*n+2, where n is the number of 
pipes).

For good results I'll presumably share main connection's load between 10 
pipes - therefore 22 threads will be spawned. Now if about 50 
connections are forwarded the number of threads rises to thousand of 
threads (or several thousands if even more connections are established).

My questions are:
- What is the cost (in memory / CPU usage) of creating such amounts of 
threads?
- Is there any 'upper boundary' that limits the number of threads? (is 
it python / OS related)
- Is that the sign of 'clumsy programming' - i.e. Is creating so many 
threads a bad habit? (I must say that it simplified the solution of my 
problem very much).

Limiting the number of threads is possible, but would affect the 
independence of data flows. (ok I admit - creating tricky algorithm 
could perhaps gurantee concurrency without spawning so many threads - 
but it's the simplest solution to this problem :) ).