[julia-users] Parallel, strange behavior of the loop after changing the value to a variable, 6 time slower

[paul analyst]

D:\install\Julia\Julia 0.3.0-prerelease-win64-ver3\Julia 0.3.0-prerelease 
ver 3>bin\julia.exe -p 8
               _
   _       _ _(_)_     |  A fresh approach to technical computing
  (_)     | (_) (_)    |  Documentation: http://docs.julialang.org
   _ _   _| |_  __ _   |  Type "help()" to list help topics
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 0.3.0-prerelease+2599 (2014-04-11 23:52 
UTC)
 _/ |\__'_|_|_|\__'_|  |  Commit bf7096c (50 days old master)
|__/                   |  x86_64-w64-mingw32

julia> procs()
9-element Array{Int64,1}:
 1
 2
 3
 4
 5
 6
 7
 8
 9

julia> tic();

julia> nheads = @parallel (+) for i=1:200000000
       int(randbool())
       end
100006468

julia> toc()
elapsed time: 2.77418807 seconds
2.77418807

julia>exit()


D:\install\Julia\Julia 0.3.0-prerelease-win64-ver3\Julia 0.3.0-prerelease 
ver 3>bin\julia.exe -p 8
               _
   _       _ _(_)_     |  A fresh approach to technical computing
  (_)     | (_) (_)    |  Documentation: http://docs.julialang.org
   _ _   _| |_  __ _   |  Type "help()" to list help topics
  | | | | | | |/ _` |  |
  | | |_| | | | (_| |  |  Version 0.3.0-prerelease+2599 (2014-04-11 23:52 
UTC)
 _/ |\__'_|_|_|\__'_|  |  Commit bf7096c (50 days old master)
|__/                   |  x86_64-w64-mingw32

julia> k=200000000
200000000

julia> tic();

julia> nheads = @parallel (+) for i=1:k
       int(randbool())
       end
99989022

julia> toc()
elapsed time: 18.631674663 seconds
18.631674663

julia>

What hapend ?

Paul