Question about profiling in GHC...
krc at cs.berkeley.edu
Mon Oct 27 10:45:15 EST 2003
On Mon, Oct 27, 2003 at 12:00:04PM -0500, glasgow-haskell-users-request at haskell.org wrote:
> When I compile my program without "-prof -auto-all" option (no
> profiling support), its execution time is about 140s (compiled with
> -O2). When compiled with profiling support, the time spent by the
> program is about 180s (I used my own timer to measure this). Of
> course, the additional 40s is caused by the profiling annotation code.
> However, the profiler says (in the ".prof" file produced at the end of
> execution) that the time spent is about 85s. I suppose that the time
> measured by the profiler is only for evaluation of the main function
> of my program (I have compiled all modules with "-prof-all"). But what
> kind of computation is performed in the rest 95s (180s - 85s) ?????
> Garbage collection ???
Yes, it's probably garbage collection. To be sure, you can run your program
with the "-t" RTS option, which will create a file in the current working
directory named "foo.stat" if the executable is named "foo". The resulting
file will contain the total amount of time spent, the mutator time, and the
GC time. (I recently ran into this problem myself...)
Kirsten Chevalier * krc at cs.berkeley.edu * Often in error, never in doubt
"But just because we're conditioned to view some things as disgusting and
immoral doesn't mean that some things aren't, in actual point of fact,
disgusting and immoral. Human sacrifice, for instance. Or cannibalism. Or Ann
Coulter." -- Dan Savage http://www.cs.berkeley.edu/~krc/
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