[Haskell-cafe] Fannkuch timings

[Daniel Fischer]

Am Dienstag, 10. Januar 2006 19:11 schrieben Sie:
> Hello Daniel,
>
> Tuesday, January 10, 2006, 7:40:24 PM, you wrote:
>
> DF> These are user/MUT times, at the moment, my machine is busy, so that
> elapsed DF> time is about double that, otherwise these times are rather
> consistently DF> reproduced (between 8.4 and 8.9 for pure, 1.7 and 1.9 for
> impure, clean DF> imperative I've done only twice, second run took 4.82s
> MUT time).
>
> on the busy machine even MUT times may be (and even should be)
> inaccurate because other threads will throw out data in CPU caches

So that explains (not surprisingly) that MUT times on the busy machine are 
slightly higher (8.9 resp. 1.9), while on an otherwise idle machine, I 
consistently got values in the range of 8.4 - 8.7 (I'm not absolutely sure, 
but I think actually the range was 8.55 - 8.7) resp. 1.7 - 1.78 secs.

The problem remains, why is the speed-ratio so different for the different 
algorithms?

Cheers,
Daniel