CPython thread starvation

[Kiuhnm]

On 4/27/2012 20:54, John Nagle wrote:
> I have a multi-threaded CPython program, which has up to four
> threads. One thread is simply a wait loop monitoring the other
> three and waiting for them to finish, so it can give them more
> work to do. When the work threads, which read web pages and
> then parse them, are compute-bound, I've had the monitoring thread
> starved of CPU time for as long as 120 seconds.
> It's sleeping for 0.5 seconds, then checking on the other threads
> and for new work do to, so the work thread isn't using much
> compute time.

How exactly are these waiting and checking performed?

Kiuhnm