What are these processes doing?

[Denys Vlasenko]

On Fri, 2009-01-23 at 15:28 -0800, Ken Teague wrote:
> Ken Teague wrote:
> > I have two processes running on a Linux box that are consuming quite a
> > lot of CPU time.
> 
> Scratch that.  After digging around a bit more, I found that these
> processes were waiting for I/O from other threads... just hanging out,
> drinking a beer and consuming a lot of (CPU) time.

I don't understand.

Waiting properly and consuming a lot of CPU time are different things.
Waiting processes should use no CPU at all, unless they are poorly coded
and wait for something by periodically polling: "did it happen?" "did it
happen?" "did it happen?"...
--
vda