[Haskell-cafe] Showing >100% CPU usage of parallel code

[Jeff Heard]

Jim, I'm actually not sure that time will report greater than 100% cpu
on ubuntu hardy. (really not sure, and don't have it available right
this moment to check).  I would however try making a computation that
will take a little longer and use the system monitor or /proc to look
at your CPU usage rather than time.  I've had good luck with GHC 6.8
using > 100% cpu, so I assume 6.10 will work much better.

On Sat, Feb 21, 2009 at 10:32 AM, Bulat Ziganshin
<bulat.ziganshin at gmail.com> wrote:
> Hello Jim,
>
> Saturday, February 21, 2009, 6:17:54 PM, you wrote:
>
>> main = a `par` b `par` c `pseq` print (a + b + c)
>
> two things:
> 1) that are grouping order? may be,
> a `par` (b `par` (c `pseq` print (a + b + c))) ?
>
> 2) i recommend you to use 2 *same* computations.
> otherwise, it's easily possible that one of them needs much more time
> that the rest
>
>
>>     where
>>         a = ack 3 10
>>         b = fac 42
>>         c = fib 34
>
>> fac 0 = 1
>> fac n = n * fac (n-1)
>
>> ack 0 n = n+1
>> ack m 0 = ack (m-1) 1
>> ack m n = ack (m-1) (ack m (n-1))
>
>> fib 0 = 0
>> fib 1 = 1
>> fib n = fib (n-1) + fib (n-2)
>> --------------------
>
>> Thanks,
>
>> Jim
>
>
>
>
>
> --
> Best regards,
>  Bulat                            mailto:Bulat.Ziganshin at gmail.com
>
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