[Python-ideas] Preallocated tuples and dicts for function calls

[Martin Bammer]

Hi,

what about the idea that the interpreter preallocates and preinitializes
the

tuples and dicts for function calls where possible when loading a module?


Before calling a function then the interpreter would just need to update
the

items which are dynamic and then call the function.


Some examples:


msgpack.unpackb(b'\x93\x01\x02\x03', use_list=False, raw=False)


The above function call needs a tuple with 1 entry and a dict with 2
entries.

All entries are constant. So in this case the interpreter can immediately

execute the function call.


Without the optimization the interpreter would need to:

- create new tuple (allocate memory)

- write constant into first tuple index.

- create dict (allocate memory)

- add key+value

- add key+value

- call function



Another example:


foo(bar, 3, 5, arg1=bar1, arg2=True)


The above needs a tuple with 3 entries. 2 of them are constant. And a dict

with 2 entries. 1 of them is constant.


With the optimization:

- write bar into first tuple index.

- replace first key+value pair in the dict.

- call function


Without the optimization:

- create new tuple (allocate memory)

- write bar into first tuple index.

- write constant into second tuple index.

- write constant into third tuple index.

- create dict (allocate memory)

- add key+value

- add key+value

- call function



If this idea is possible to implement I assume the function calls would

receive a great speed improvment.


Best regards,

Martin
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