Question about GUM

Changming Ma
Thu, 20 Jun 2002 21:58:35 -0500 (CDT)

Hi there,

I'm getting confused of the run-time system behavior of GUM. When I ran a quicksort 
program in GUM with profiling flag, I got different "task" distributions in the PS 
file generated everytime, e.g., the peak of task number may be 19 at the first time 
and 48 at the second. While it's quite reasonable that the clock cycles vary 
dramatically, it's somewhat strange to me that the task distributions are so 
different. Any hints? I do appreaciate it.

BTW, seems the program does not stop if the input list has more than 350 elements, 
althought it works fine otherwise. Will it get better if I use an SMP system?

Thanks in advance.

PS: I'm using GUM-4.06, PVM3, RH LINUX6.2 on a single processor system.
Program and RTS flags

quicksort +RTS -qP -sstderr
grs2gr *quicksort.???.gr >
gr2ps -o

--source code
module Main(main) where

import System(getArgs)
import Parallel

forceList :: [a] -> ()
forceList [] = ()
forceList (x:xs) = x `seq` forceList xs
quicksortF []      = []
quicksortF [x]     = [x]

quicksortF (x:xs)  = 
 (forceList losort) `par`
 (forceList hisort) `par`
 losort ++ (x:hisort)
   losort = quicksortF [y|y <- xs, y < x] 
   hisort = quicksortF [y|y <- xs, y >= x]
args_to_IntList :: [String] -> [Int]
args_to_IntList a = if length a < 1
		      then error "Parallel Quick Sort: no enough args \n"
		      else map read a
main = putStr ("get " ++ (show (quicksortF l))++"\n")

l = [	658986,123141,737929,681645,329651,