threadDelay problem

Simon Marlow simonmar at
Wed Jan 7 12:38:11 EST 2004

> The idea is to stop a Haskell prog with no runable threads or events
> to process hogging CPU time. I was a bit dissapointed to find 
> that despite
> this on my (otherwise idle) machine the above code was still 
> using 96% of cpu time.
> But fiddling about a bit I found that by changing the thread 
> delay in the
> main loop to 20 mS the CPU usage dropped to 1% or so, which 
> is much more
> acceptable (well it did say 1/50 th second accuracy in the docs :-).

Yes, threadDelay will round the interval down to the nearest multiple of
the resolution, so you were effectively using threadDelay 0.  This ought
to be mentioned in the documentation.


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