[Haskell-cafe] Possible bug in Criterion or Statistics package

[Aleksey Khudyakov]

On 10.08.2012 22:20, Till Berger wrote:
>>>> So I am not sure if this is a bug in Criterion itself, the Statistics
>>>> package or any dependency or if I am doing something obviously wrong. I
>>>> would be grateful if someone could look into this as it is holding me
>>>> back from using Criterion for benchmarking my code.
>>>>
>>> I would suspect Statistics.Resampling.resample. From quick glance
>>> criterion doesn't use any concurrent stuff. I'll try create smaller test
>>> case
>>
>> It looks like I'm wrong. I obtained event log from crashing program
>> and resample completed its work without problems. Crash occured later.
>> Next
>> suspect is bootstrapBCA itself. It uses monad-par to obtain
>> parallelism[1].
>>
>> I tried to create smaller test case without any success.
>>
>>
>>
>> [1]
>> https://github.com/bos/statistics/blob/master/Statistics/Resampling/Bootstrap.hs#L84
>>
>
> Replacing "runPar $ parMap" with a simple "map" on that line seems to
> fix the bug. At least I could not reproduce it anymore on several runs
> with my original test case. So it seems to be a bug in the Par monad
> package as this change shouldn't alter the program's behaviour, should it?
>
Looks like this is the case. But reducing test case to reasonable size 
(e.g. removing most of criterion and statistics could be quite difficult