do not benchmark yield

primes.py

import time

def get_primes(n):
  compo=set()
  for i in xrange(2, n):
    if i in compo: continue
    yield i
    compo.update(xrange(i*2, n,i))

def benchmark(f, n):
  def wrapped(*a, **kw):
    t0=time.time()
    for i in xrange(n): f(*a, **kw)
    print "dt=", time.time()-t0
  return wrapped

benchmark(get_primes, 500)(10000)