Help: Parallel processing on a simple tasks doesn't work correctly

@Holo wrote:

Hi, anybody here who are good at parallel processing in Rhino Python?
I made a simple test but the results doesn’t seem right.

I have tried to make a script that lets the cpu calculate n += 1 for 1 second in default one core mode and THEN set up 500 tasks that runs for 1 second IF time ran is less than 1 second. (That should result in x number of tasks that ran for 1 second and the rest of the 500 to be returned as

import System.Threading.Tasks as tasks
import rhinoscriptsyntax as rs
import time
import random


def calculateSinglecore(time2Run):
    time1=time.time()
    i = 0
    while True:
        i += 1
        if time.time()-time1 > time2Run:
            break
    return int(i/time2Run)

def calculateMulticore(time2Run):
    points=range(500)
    results=range(500)
    
    timeStart=time.time()
    
    def calculate(i):
        n=0
        while time.time()-timeStart < time2Run:
            n += 1
        results[i] = n
    
    tasks.Parallel.ForEach(xrange(len(points)), calculate)
    
    results = [x for x in results if x != 0]
    print len(results), "Threads started"
    print results
    ### Add up all calculations
    Total = sum(results)
    ### measure actual time used and divide sum to get calculations within one second
    runTime=time.time()-timeStart
    result = int(Total/runTime)
    return result

test1 = calculateSinglecore(1)
print test1,"calculations per second in serial processing" 
test2 = calculateMulticore(1)
print test2,"calculations per second in parallel processing"

print round(test2/test1,2), "times faster in parallel"

My results on a 12 core system is:

482991 calculations per second in serial processing
25 Threads started
[45542, 38472, 44854, 45001, 43605, 43845, 48035, 45841, 45119, 43848, 47106, 47589, 36292, 41124, 44695, 43304, 38177, 49657, 47278, 41905, 46837, 44746, 46086, 50670, 45309]
1105097 calculations per second in parallel processing
2.29 times faster in parallel

NOTE: Some thing I don’t understand is that if I set the number of tasks (points and results) to 2 instead of 500 I get the same result… and each task has a higher count…

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