[Haskell-cafe] GHC timings

Daniel Fischer daniel.is.fischer at googlemail.com
Thu Jan 20 16:06:25 CET 2011

On Thursday 20 January 2011 15:18:51, S. Doaitse Swierstra wrote:
> I have small program UULib which i use for checking some timing
> information.
> When I compile with ghc 7 and profiling information I get the timings
> which are more or less what I expect. If I however recompile without
> profiling tome consumed goes up by a factor of 20!

Perhaps profiling prevents the application of an optimisation which is in 
fact a pessimisation for your programme.
Does looking at the generated Core reveal something?
(if you make the code available, others could look too)
What are the times when you compile with -O[2]?

> 1) Am I misinterpreting the results?
> 2) If not, does this look familiar to anyone?
> 3) If so, whether should I look first to see what is going on here?

Look at the Core, ask on glasgow-haskell-users/open a ticket so that you 
have a better chance of getting the attention of an expert (the GHC team 
don't regularly follow the cafe).

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