In Python cProfile, what is the difference between calls count and primitive calls count?

Question

When I display profiling data using pstats, the first column is the number of calls for each function.

However, when I sort data, I have choice between calls, ncalls and pcalls keys. Documentation says that calls and ncalls are call count, when pcalls is primitive call count. Is sorting by calls or ncalls is the same? What is different with pcalls?

Answer 1

http://docs.python.org/2/library/profile.html#module-cProfile

We define primitive to mean that the call was not induced via recursion.

...when the function does not recurse, these two values are the same

Sorting by calls or ncalls is the same.

---

When there are two numbers in the first column (for example, 43/3), then the latter is the number of primitive calls, and the former is the actual number of calls. Note that when the function does not recurse, these two values are the same, and only the single figure is printed:

In [43]: def a(i):
   ....:     if i == 0:
   ....:         return
   ....:     a(i-1)
   ....:


In [54]: %prun a(0)
  ncalls  tottime  percall  cumtime  percall filename:lineno(function)
       1    0.000    0.000    0.000    0.000 <ipython-input-43-25b7f3d268b8>:1(a)


In [55]: %prun a(1)
  ncalls  tottime  percall  cumtime  percall filename:lineno(function)
     2/1    0.000    0.000    0.000    0.000 <ipython-input-43-25b7f3d268b8>:1(a)


In [56]: %prun a(3)
  ncalls  tottime  percall  cumtime  percall filename:lineno(function)
     4/1    0.000    0.000    0.000    0.000 <ipython-input-43-25b7f3d268b8>:1(a)