c# - Multiple Images Processing using Parallel and Task -

i'm writing c# windows form application provide end-to-end image processing system. system consists of many image processing blocks (i.e, scaler, noise reduction,...), each block algorithm written in c, , i've built each of them dlls , call them c# application.

my system this:

(main) input1 -> block1 -> block2  (ig) input2 -> block3 -> block4  -> mux -> output  (pg) input3 -> block5 -> block6 

at moment, code i'm using this:

   task.factory.startnew(() => parallel.for(0, loop_num, =>             {                 parallel.invoke(                 () =>                 {                     main(i);                 },                 () =>                 {                     ig(i);                 },                 () =>                 {                     pg(i);                 }                 );                 mux(i);             }), taskcreationoptions.longrunning); 

but see application taking long time complete few images. i'm not @ c# , self study parallel , task via examples.

i don't know if code enough on handle multiple processing, or there better way? start thread help/suggest.