entries in profile results

[Simon Marlow]

On 12/05/2011 01:30, Kazu Yamamoto (山本和彦) wrote:

> I'm taking profile for my program with -auto-all -caf-all. I found
> that I don't understand what "entries" means.
>
> An IO function in my program should be called N times but "entries"
> shows 3N. I inserted putStrLn in that function and ensured that it was
> called just N times.
>
> Please tell me what "entries" mean exactly.

It's not clear what "entries" means exactly.  GHC's profiler is lacking 
a semantics, so what it actually does is anyone's guess; fortunately it 
does something more-or-less reasonable often enough to be useful.  We 
have tickets that point out some problems like the one you reported, e.g.:

   http://hackage.haskell.org/trac/ghc/ticket/4414

my long-term hope is that we can figure out a good semantics for 
cost-centre stacks, implement it, and close all these tickets (at the 
same time we'd find out how to get sensible stack-traces too, albeit 
only in profiling mode).  This is a wall I've bounced off a few times 
though.

Cheers,
	Simon