Added the cProfile module.

Based on lsprof (patch #1212837) by Brett Rosen and Ted Czotter.
With further editing by Michael Hudson and myself.
History in svn repo: http://codespeak.net/svn/user/arigo/hack/misc/lsprof

* Module/_lsprof.c is the internal C module, Lib/cProfile.py a wrapper.
* pstats.py updated to display cProfile's caller/callee timings if available.
* setup.py and NEWS updated.
* documentation updates in the profiler section:
   - explain the differences between the three profilers that we have now
   - profile and cProfile can use a unified documentation, like (c)Pickle
   - mention that hotshot is "for specialized usage" now
   - removed references to the "old profiler" that no longer exists
* test updates:
   - extended test_profile to cover delicate cases like recursion
   - added tests for the caller/callee displays
   - added test_cProfile, performing the same tests for cProfile
* TO-DO:
   - cProfile gives a nicer name to built-in, particularly built-in methods,
     which could be backported to profile.
   - not tested on Windows recently!

Lib/test/test_cProfile.py

@@ -0,0 +1,123 @@
+"""Test suite for the cProfile module."""
+
+import cProfile, pstats, sys
+
+# In order to have reproducible time, we simulate a timer in the global
+# variable 'ticks', which represents simulated time in milliseconds.
+# (We can't use a helper function increment the timer since it would be
+# included in the profile and would appear to consume all the time.)
+ticks = 0
+
+# IMPORTANT: this is an output test.  *ALL* NUMBERS in the expected
+# output are relevant.  If you change the formatting of pstats,
+# please don't just regenerate output/test_cProfile without checking
+# very carefully that not a single number has changed.
+
+def test_main():
+    global ticks
+    ticks = 42000
+    prof = cProfile.Profile(timer, 0.001)
+    prof.runctx("testfunc()", globals(), locals())
+    assert ticks == 43000, ticks
+    st = pstats.Stats(prof)
+    st.strip_dirs().sort_stats('stdname').print_stats()
+    st.print_callees()
+    st.print_callers()
+
+def timer():
+    return ticks
+
+def testfunc():
+    # 1 call
+    # 1000 ticks total: 270 ticks local, 730 ticks in subfunctions
+    global ticks
+    ticks += 99
+    helper()                            # 300
+    helper()                            # 300
+    ticks += 171
+    factorial(14)                       # 130
+
+def factorial(n):
+    # 23 calls total
+    # 170 ticks total, 150 ticks local
+    # 3 primitive calls, 130, 20 and 20 ticks total
+    # including 116, 17, 17 ticks local
+    global ticks
+    if n > 0:
+        ticks += n
+        return mul(n, factorial(n-1))
+    else:
+        ticks += 11
+        return 1
+
+def mul(a, b):
+    # 20 calls
+    # 1 tick, local
+    global ticks
+    ticks += 1
+    return a * b
+
+def helper():
+    # 2 calls
+    # 300 ticks total: 20 ticks local, 260 ticks in subfunctions
+    global ticks
+    ticks += 1
+    helper1()                           # 30
+    ticks += 2
+    helper1()                           # 30
+    ticks += 6
+    helper2()                           # 50
+    ticks += 3
+    helper2()                           # 50
+    ticks += 2
+    helper2()                           # 50
+    ticks += 5
+    helper2_indirect()                  # 70
+    ticks += 1
+
+def helper1():
+    # 4 calls
+    # 30 ticks total: 29 ticks local, 1 tick in subfunctions
+    global ticks
+    ticks += 10
+    hasattr(C(), "foo")                 # 1
+    ticks += 19
+    lst = []
+    lst.append(42)                      # 0
+    sys.exc_info()                      # 0
+
+def helper2_indirect():
+    helper2()                           # 50
+    factorial(3)                        # 20
+
+def helper2():
+    # 8 calls
+    # 50 ticks local: 39 ticks local, 11 ticks in subfunctions
+    global ticks
+    ticks += 11
+    hasattr(C(), "bar")                 # 1
+    ticks += 13
+    subhelper()                         # 10
+    ticks += 15
+
+def subhelper():
+    # 8 calls
+    # 10 ticks total: 8 ticks local, 2 ticks in subfunctions
+    global ticks
+    ticks += 2
+    for i in range(2):                  # 0
+        try:
+            C().foo                     # 1 x 2
+        except AttributeError:
+            ticks += 3                  # 3 x 2
+
+class C:
+    def __getattr__(self, name):
+        # 28 calls
+        # 1 tick, local
+        global ticks
+        ticks += 1
+        raise AttributeError
+
+if __name__ == "__main__":
+    test_main()