Does anyone know anything about threadpools?

[wonkey_monkey]

I usually internally multithread my filters, but with my latest one I'm running into a problem because the overhead for creating the threads is too high, and offsets any speed advantage.

I did a bit of Googling, and found out about threadpools - create a bunch of threads once, and then using conditional variables to signal to them to do work when required. That way, the thread creation overhead is removed, because the threads are created once on construction of the filter, not per frame (or several times per frame, as in my case).

But, as usual, I don't really know what I'm doing and I can't get it to work properly. It seems like there's some kind of timing issue where one of the threads sometimes fails to get the notification. What's really annoying is that as soon as I add more code to debug it, that slows things down enough that the problem doesn't happen, which makes it hard to figure out.

So does anyone here understand threadpools who could help me figure out what's going wrong?