test.py

import random
import time 
import threading
from itertools import product
from Queue import Queue
import numpy

class Thing(object):
  def __init__(self, key):
    self.key = key

class test(object):
  def __init__(self, n_threads=2):
    self.n_threads = n_threads
  def __call__(self, f):
    def g(*args, **kwargs):
      t0 = time.time()
      threads = []
      for i in range(self.n_threads):
        t = threading.Thread(target=f)
        t.start()
        threads.append(t)
      for t in threads:
        t.join()
      t1 = time.time()
      return t1-t0
    return g


table = {}
crumbs = ['dfgdg', 'sdf', 'brtq', 'poxcva', 'ad', 'dgwev', 'xvqwrxs']
locks = [threading.Lock() for i in range(16)]
global_lock = threading.Lock()

## Build object lookup table
for i,p in enumerate(product(crumbs, crumbs, crumbs)):
  k = ':'.join(p)
  table[k] = Thing(k)

@test(n_threads=4)
def f1():
  for p in product(crumbs, crumbs, crumbs):
    k = ':'.join(p)
    with locks[hash(k)&15]:
      t = table[k]

@test(n_threads=4)
def f2():
  for p in product(crumbs, crumbs, crumbs):
    k = ':'.join(p)
    with global_lock:
      #t = Thing(k)
      t = table[k]

@test(n_threads=4)
def f3():
  for p in product(crumbs, crumbs, crumbs):
    k = ':'.join(p)
    t = Thing(k)

f21 = []
f31 = []
for i in range(10):
  f21.append(f2()/f1())
  f31.append(f3()/f1())

print "speedup of lock table over global lock: {0:.2f}x".format(numpy.mean(f21))
print "speedup of lock table over re-instantiation: {0:.2f}x".format(numpy.mean(f31))