Does threadscope help? It should be of some use since it is designed for debugging parallel programs. Cheers, Vanessa On 12/28/18 2:19 AM, ducis wrote:

Hi all,

I am working on parallelising some program, however I just found out that without inserting any parallism manually the program is already parallelised, presumably by some of the libraries referenced, as long as I enable -threaded and +RTS -N8.

Unfortunately this parallism are actually slowing down my program, probably due to being of too fine granularity. For example, with +RTS -N8 I have    47.03user 38.06system 0:21.68elapsed 392%CPU While with +RTS -N1 I have 16.57user 0.45system 0:17.02elapsed 100%CPU

In .prof file I can't find whether a function fired a spark or how much 'system' time a function used. Nor can I find any names of functions/modules browsing through eventlog with ghc-events. Is there a way to find out which functions/modules are causing any parallelism at all?

I am also trailing the post with the imports I used in case anyone immediately recognises parallelism by default in the package. import Control.DeepSeq import GHC.Generics (Generic, Generic1) import Text.Parsec                                                                        

import Data.List                                                                          

import Data.Vector.Unboxed(fromList, (!))                                                  import qualified Data.Vector as V                                                          import qualified Data.Map as M                                                             import qualified Data.Set as S                                                             import Data.Char                                                                          

import Control.Applicative((*>),(<*))                                                     

import Test.QuickCheck.Monadic                                                            

import Test.QuickCheck                                                                    

import Control.Monad                                                                      

import Text.Regex                                                   import Control.Applicative ((<$>), (<$), (<|>))        import GHC.Read (readLitChar)                          import Data.Char(isPrint)                              import Text.ParserCombinators.ReadP                                             import Text.Show.Pretty                                                                   

import Data.Functor                                                                       

import Data.Maybe                                                                         

import System.Environment(getArgs) import Text.Read(readMaybe)                                                               

import Text.Printf                                                                               

import Data.Dynamic                                                                       

import Debug.Trace                                                                        

import Data.Ratio                                                                           

import qualified Data.DList as D                                                           import Control.Monad.Trans.Writer.Strict                                                             

import Control.Monad.Trans.Class                                                          

import Data.Typeable(Typeable)                                                            

import qualified Data.HashMap.Lazy as H                                              

Best, ducis    

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