[Haskell-cafe] Removing alternate items from a list

John Lato jwlato at gmail.com
Thu Jun 10 05:14:31 EDT 2010

> From: Markus L?ll <markus.l2ll at gmail.com>
> So out of curiosity i took the definitions given in this thread, and
> tried to run timing-tests.
> Here's what I ran:
>> ghc -prof -auto-all -o Test Test.h
>> Test +RTS -p
> and then looked in the Test.prof file.

I think this is a poor approach for timing tests, for two reasons:

1) -O or -O2.  Reporting performance results from non-optimized builds
is often highly misleading.
2) -auto-all inhibits performance of code, sometimes significantly.

You'd be better off using a non-profiling build and criterion.  Plus
criterion does the statistics for you and warns about possibly invalid


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