[Haskell-cafe] Concurrency performance problem

[Łukasz Dąbek]

What do you exactly mean? I have included link to full source listing:
http://hpaste.org/83460.

--
Łukasz Dąbek

2013/3/4 Don Stewart <dons00 at gmail.com>:
> Depends on your code...
>
> On Mar 4, 2013 6:10 PM, "Łukasz Dąbek" <sznurek at gmail.com> wrote:
>>
>> Hello Cafe!
>>
>> I have a problem with following code: http://hpaste.org/83460. It is a
>> simple Monte Carlo integration. The problem is that when I run my
>> program with +RTS -N1 I get:
>> Multi
>> 693204.039020917 8.620632s
>> Single
>> 693204.039020917 8.574839s
>> End
>>
>> And with +RTS -N4 (I have four CPU cores):
>> Multi
>> 693204.0390209169 11.877143s
>> Single
>> 693204.039020917 11.399888s
>> End
>>
>> I have two questions:
>>  1) Why performance decreases when I add more cores for my program?
>>  2) Why performance of single threaded integration also changes with
>> number of cores?
>>
>> Thanks for all answers,
>> Łukasz Dąbek.
>>
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