cfe_select_class_simulation.py

import sys
import time
import numpy as np
import json

CF_HASHTABLESIZE = 8192

def stringhash(s, seed, max):
    # Implementation of StringHash() from:
    # https://github.com/lpefferkorn/cfe-rsplaytime/blob/master/cfe-rsplaytime.py
    h = np.uint32(seed)
    for i in bytearray(s):
        h += np.uint32(i)
        h += np.uint32(h << 10)
        h ^= np.uint32(h >> 6)

    h += np.uint32(h << 3)
    h ^= np.uint32(h >> 11)
    h += np.uint32(h << 15)

    return np.uint32(h & (max - 1))


def get_index_changed(hostname, ip, list_length, ti):
    # changed calculation of hash time as seed
    ti -= ti%CF_HASHTABLESIZE
    hashstr = '{0}+{1}+{2}'.format(hostname, ip, ti)
    hash_value = stringhash(hashstr, 0, CF_HASHTABLESIZE)

    return int(list_length * hash_value / float(CF_HASHTABLESIZE))

def get_index_original(hostname, ip, list_length):
    # original calculation of hash
    hashstr = '{0}+{1}+{2}'.format(hostname, ip, 0)
    hash_value = stringhash(hashstr, 0, CF_HASHTABLESIZE)
    start = 0

    return int(list_length * hash_value / float(CF_HASHTABLESIZE))


def get_splaytime(hostname, ip):
    # implementation of GetSplay() in cf-execd/execd-config.c
    hashstr = '{0}+{1}+{2}'.format(hostname, ip, 0)
    hash_value = stringhash(hashstr, 0, CF_HASHTABLESIZE)
    splay = np.float64(hash_value / float(CF_HASHTABLESIZE))
    return int(4*60*splay)


def main():
    mpses = ['mps1', 'mps2', 'mps3', 'mps4']
    data = {}
    ti = time.time()
    for i in range(4):
        for j in range(1, 201):
            host_num = j+i*100
            hostname = "dc1-app{0}.internal.local.net".format(host_num)
            ip = "10.1.{0}.{1}".format(i, j)
            splaytime = get_splaytime(hostname, ip)

            mps_orig = mpses[get_index_original(hostname, ip, len(mpses))]
            select_class_changed = mpses[get_index_changed(hostname, ip, len(mpses), ti+splaytime)]

            if splaytime not in data:
                data[splaytime] = []
            data[splaytime].append({'hostname': hostname, 'select_class_original': mps_orig, 'select_class_changed': select_class_changed })


    #print json.dumps(data, indent=2, sort_keys=True)

    mps_count = []

    for seconds in sorted(data.keys()):
        if seconds%60 == 0:
            temp_data = { 'select_class_original': {}, 'select_class_changed': {} }
            mps_count.append(temp_data)

        for i in ['select_class_original', 'select_class_changed']:
            for j in data[seconds]:
                if j[i] not in temp_data[i]:
                    temp_data[i][j[i]] = 0

                temp_data[i][j[i]] += 1

    for minute, methods in enumerate(mps_count):
        print "During Minute: {0}".format(minute+1)
        for method in methods:
            print "{0}:".format(method)
            for mps in methods[method]:
                print "{0} was selected by {1} hosts".format(mps, methods[method][mps])
            print ""
        print ""



if __name__ == '__main__':
    main()