Unexpected output of (Python) time.clock()

Question

Having some trouble understanding the output from time.clock():

Linux 3.5.0-17-generic #28-Ubuntu SMP Tue Oct 9 19:31:23 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux Distributor ID: LinuxMint Description: Linux Mint 14 Nadia Release: 14 Codename: nadia

Python 2.7.3 (default, Sep 26 2012, 21:51:14) 
[GCC 4.7.2] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>> from time import clock, sleep, time
>>> while True: sleep(1); print clock()
... 
0.03
0.03
0.03
0.03
0.03
^CTraceback (most recent call last):
  File "<stdin>", line 1, in <module>
KeyboardInterrupt
>>> while True: sleep(1); print time()
... 
1382460160.37
1382460161.37
1382460162.37
1382460163.38
1382460164.38
^CTraceback (most recent call last):
  File "<stdin>", line 1, in <module>
KeyboardInterrupt

# ...wait a few minutes...

>>> while True: sleep(1); print clock()
... 
0.04
0.04
0.04
0.04
0.04
0.04
^CTraceback (most recent call last):
  File "<stdin>", line 1, in <module>
KeyboardInterrupt
>>> 

$ cat test.py
#! /usr/bin/python

from time import sleep, time, clock

while True:
    print clock(), time()
    sleep(1)


$ python test.py
0.02 1382460623.39
0.02 1382460624.39
0.02 1382460625.39
0.02 1382460626.39
0.02 1382460627.39
0.02 1382460628.39
0.02 1382460629.4
0.02 1382460630.4
0.02 1382460631.4
0.02 1382460632.4
0.02 1382460633.4
0.02 1382460634.4
0.02 1382460635.4
0.02 1382460636.4
0.02 1382460637.41
0.02 1382460638.41
0.02 1382460639.41
0.02 1382460640.41
0.02 1382460641.41
0.02 1382460642.41
0.02 1382460643.41
0.02 1382460644.41
0.02 1382460645.41
0.02 1382460646.42
0.02 1382460647.42
0.02 1382460648.42
0.02 1382460649.42
0.02 1382460650.42
^CTraceback (most recent call last):
  File "test.py", line 7, in <module>
    sleep(1)
KeyboardInterrupt

I'm obviously missing something obvious here?

Answer 1

on Linux systems, time.clock() returns "processor time", not "wall time".