profiling question

[Simon Marlow]

Hi there,

> I have a profile that looks like this:
> 
> COST CENTRE          MODULE     %time %alloc
>  
> GC                   GC         164.9    0.0
> subsumes             Cover       98.7  945.8
> sub                  Cover        0.6   75.7
> c_unify              Cover        0.4   15.9
> compose              Cover        0.2    4.5
> countFreqs           Cover        0.0    2.4
> lexer                BGKBParser   0.0    1.5
> isNameChar           BGKBParser   0.0    1.3
>                                                 
> 
> and the detail:
> 
>             fits         Cover       397920    0.0   0.9     
> 99.9  93.0
>              subsumes    Cover     -1452515424   98.7 945.8     99.9 
> 92.1
>               sub        Cover     42784164    0.6  69.4      
> 0.6  69.4
>               c_unify    Cover      6760353    0.4  15.9      
> 0.6  26.7  
> 
> 
> What does 945.8% mean for my "subsumes" function? Are these 
> percents not
> out of 100 then? Could it be taking that much time because 
> it's doing an
> exceptional amount of memory allocation? 

Thanks for the report.  It looks like all that happened is the 32-bit
counter that measures allocations has overflowed, leading to a lot of
bogus results.  Also, the _scc_ count has obviously overflowed in your
example.  I'll see if I can bump these to 64-bit counter without too
many adverse effects.  

Cheers,
	Simon