To speedup Python startup, it may be interesting to not create useless many functions and classes in operator.py: "from _operator import *" will remove them a few line later.

What do you think of moving the Python implementation of the operator module inside in the else block of "try/except ImportError" section?

See attached operator.py for an example.

It adds an ugly level of indentation, but it's for performances!

Another option is to add a _pyoperator module.

Using the microbenchmark I get (standard version):

./python -m timeit "import sys; modname='operator'" "__import__(modname); del sys.modules[modname]"
1000 loops, best of 3: 460 usec per loop

Victor's version:

./python -m timeit "import sys; modname='operator'" "__import__(modname); del sys.modules[modname]"
1000 loops, best of 3: 355 usec per loop

Importing _operator directly:

./python -m timeit "import sys; modname='_operator'" "__import__(modname); del sys.modules[modname]"
10000 loops, best of 3: 35.7 usec per loop

Extrapolating from what I did with decimal, I guess a _pyoperator
version could get down to something like 70 usec.

To be fair, for the startup time I can't really detect any difference between importing _operator directly and the current setup.

Another option is to add a _pyoperator module.

Attached builtin_operator.patch patch implements this option: operator.c becomes the main operator module, _pyoperator is the pure Python implementation (don't use "from _operator import *" anymore).

With the patch:

$ ./python -m timeit "import sys; modname='_pyoperator'" "__import__(modname); del sys.modules[modname]" 
1000 loops, best of 3: 276 usec per loop

$ ./python -m timeit "import sys; modname='operator'" "__import__(modname); del sys.modules[modname]" 
10000 loops, best of 3: 22.7 usec per loop

The patch is huge because files are renamed: see builtin_operator_diff.patch for the diff.

Without the patch:

$ ./python -m timeit "import sys; modname='operator'" "__import__(modname); del sys.modules[modname]" 
1000 loops, best of 3: 289 usec per loop

$ ./python -m timeit "import sys; modname='_operator'" "__import__(modname); del sys.modules[modname]" 
10000 loops, best of 3: 21.4 usec per loop

"import operator" is 12.7x faster (289 usec => 22.7 usec) with builtin_operator.patch.

Why not:

try:
from _operator import *
except ImportError:
from _pyoperator import *

Why not:

try:
from _operator import *
except ImportError:
from _pyoperator import *

Let's try (I replaced operator.py with these 4 lines).

$ ./python -m timeit "import sys; modname='operator'" "__import__(modname); del sys.modules[modname]; del sys.modules['_operator']" 
10000 loops, best of 3: 165 usec per loop

$ ./python -m timeit "import sys; modname='operator'" "__import__(modname); del sys.modules[modname]" 
10000 loops, best of 3: 136 usec per loop

"import operator" is only 2x faster (289 usec => 136 usec). It's less interesting. And what would be the purpose of a file of 4 line which containing "import *"? Do you think that PyPy, IronPython and Jython will reuse such trampoline/wrapper?

"import operator" is only 2x faster (289 usec => 136 usec). It's less
interesting.

The real question for me is: why are you interested in speeding up the
import of the operator module? 200 µs won't make a visible difference.

And what would be the purpose of a file of 4 line which
containing "import *"?

To make it obvious that there are two implementations, one of which is
a fallback.

I understand the desire to speed things up, but either the four-line facade
module or else a single module is probably required by PEP-399.

"The real question for me is: why are you interested in speeding up the
import of the operator module? 200 µs won't make a visible difference."

Alone, the gain is useless, but it's like the work done in Python 3.4 to avoid loading some modules at startup. The overall idea is to have a fast startup time.

I heard that Python 3 startup time is a major blocker point for Mercurial for example.

But maybe this specific issue is not worth the trouble. (Other parts should be optimized.)