It's slow, uses a ton of memory

The following code spawns 100 threads in under 2 seconds and uses < 40MB?

>perl -Mthreads -le"print time;@t=map{threads->new(sub{sleep 300})}1..
+100;print time;<>"
1107144770
1107144772
[download]

I agree they aren't doing much, and that is probably considerably slower than you can spawn 100 processes--but if you need the parent to communicate with the children and vice versa, then you'd need to a lot more work using fork.

It is true that there are some inconvenient restrictions (some of which could be alleviated), and you do have to learn a few simple techniques for getting the best from them--like not loading anything you don't want shared before you spawn your threads--but they are stable and very usable.

On Win32, they are infinitely preferable to fork, but I realise that that is a restriction of the platform. I can well see why anyone on unix wouldn't bother with them unless they really needed bi-directional communications.

I agree that the implementation is imperfect, but having spent a little time looking into the work that they are doign, I think teh guys that got them to where they are are did an brillaint job given the task they faced.