[Haskell-cafe] GHC 6.10, strange behaviour when profiling?

[Don Stewart]

Could you please file this as a bug at this address,

    http://hackage.haskell.org/trac/ghc/newticket?type=bug

Cheers,
  Don

ales.bizjak0:
> Hello,
> 
> I'm experiencing some strange behaviour with GHC 6.10 and would like an  
> explanation why.
> 
> Here's the problem. With GHC 6.8.[23] memory usage of a program was about  
> 250mb (computing pi to 10^6 decimals).
> Now I tried recompiling and running with GHC 6.10 and I got more than  
> 1.4gb before I killed it, so naturally I tried profiling but
> here's the strangeness. When I compile for profiling with -prof -auto-all  
> and run with +RTS -p -RTS memory use is
> still about the same as before (> 1.4gb), but when I try running with +RTS 
> -hc -RTS memory only reaches about 250mb.
> 
> What is the explanation for this behaviour?
> 
> I would send a program but it requires HERA, which is not on hackage ...
> 
> Here is the output of -s
> 
> ./Test 100000 +RTS -s
>       47,467,176 bytes allocated in the heap
>       18,046,776 bytes copied during GC
>        9,215,104 bytes maximum residency (6 sample(s))
>          711,520 bytes maximum slop
>               80 MB total memory in use (11 MB lost due to fragmentation)
> 
>   Generation 0:    84 collections,     0 parallel,  0.01s,  0.01s elapsed
>   Generation 1:     6 collections,     0 parallel,  0.01s,  0.01s elapsed
> 
>   INIT  time    0.00s  (  0.00s elapsed)
>   MUT   time    3.66s  (  3.71s elapsed)
>   GC    time    0.02s  (  0.02s elapsed)
>   RP    time    0.00s  (  0.00s elapsed)
>   PROF  time    0.00s  (  0.00s elapsed)
>   EXIT  time    0.00s  (  0.00s elapsed)
>   Total time    3.68s  (  3.73s elapsed)
> 
>   %GC time       0.5%  (0.6% elapsed)
> 
>   Alloc rate    12,982,553 bytes per MUT second
> 
>   Productivity  99.5% of total user, 97.9% of total elapsed
> 
> 
> 
> 
> ./Test 100000 +RTS -s -hc
>       47,471,160 bytes allocated in the heap
>       18,637,752 bytes copied during GC
>       13,580,144 bytes maximum residency (37 sample(s))
>          810,712 bytes maximum slop
>               33 MB total memory in use (7 MB lost due to fragmentation)
> 
>   Generation 0:    85 collections,     0 parallel,  0.02s,  0.02s elapsed
>   Generation 1:    37 collections,     0 parallel,  0.00s,  0.01s elapsed
> 
>   INIT  time    0.00s  (  0.00s elapsed)
>   MUT   time    3.67s  (  3.73s elapsed)
>   GC    time    0.02s  (  0.03s elapsed)
>   RP    time    0.00s  (  0.00s elapsed)
>   PROF  time    0.00s  (  0.00s elapsed)
>   EXIT  time    0.00s  (  0.00s elapsed)
>   Total time    3.70s  (  3.77s elapsed)
> 
>   %GC time       0.6%  (0.8% elapsed)
> 
>   Alloc rate    12,941,165 bytes per MUT second
> 
>   Productivity  99.2% of total user, 97.4% of total elapsed
> 
> 
> 
> 
> -- 
> Best regards, Aleš
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