[Python-Dev] Idea for a fast calling convention

[Michael Hudson]

"Raymond Hettinger" <raymond.hettinger at verizon.net> writes:

> I've been working on ways to speedup parameter passing for function
> calls.  It's somewhat expensive to pull parameters off of the stack,
> assemble them into a new tuple, have the function disassemble the tuple,
> and ultimately free the tuple.

Yahbut... that doesn't actually happen all that often.

> METH_NOARGS and METH_O show nice speed-ups by skipping the tuple packing
> and unpacking.  Since they are handled as special cases, that approach
> doesn't handle the general case with multiple or optional arguments.

Oh, you're talking about builtin functions.

> My idea is for a new flag, METH_STACK, that generalizes (and potentially
> replaces) METH_NOARGS AND METH_O.
>
> When CALL_FUNCTION sees the flag, it dispatches (*meth)(self, &stack,
> numargs).
>
> On the receiving end, the arguments get retrieved with analogues to
> PyArg_ParseTuple() and PyArg_UnpackTuple() which access the parameters
> directly and do not need a tuple as a carrier.

Have you seen my "function optimization reorganization" patch on SF?
It's a somewhat different result of somewhat similar thinking.

http://python.org/sf/876193

Cheers,
mwh

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