Projects to optimize CPython 3.7

See also Projects to optimize CPython 3.6.

Big projects

• Multiple interepters per process
  • “solving multi-core Python”
  • https://mail.python.org/pipermail/python-ideas/2015-June/034177.html
  • http://ericsnowcurrently.blogspot.fr/2016/09/solving-mutli-core-python.html
• PyParallel
• Gilectomy: GIL-less CPython
• Add a JIT to CPython? :-) (see Pyston and Pyjion)

Smaller projects

• MERGED: Issue #26110: LOAD_METHOD and CALL_METHOD
  • Issue #29263: Implement LOAD_METHOD/CALL_METHOD for C functions
• Issue #28158: Implement LOAD_GLOBAL opcode cache
  • Issue #26219: implement per-opcode cache in ceval
  • Issue #10401: Globals / builtins cache
• Free list for single-digits ints
• FASTCALL
  • PENDING: tp_fastcall: Issue #29259: Add tp_fastcall to PyTypeObject: support FASTCALL calling convention for all callable objects
  • REJECTED: Add tp_fastnew and tp_fastinit to PyTypeObject, 15-20% faster object instanciation
• Convert more C functions to METH_FASTCALL and Argument Clinic
  • Argument Clinic should understand *args and **kwargs parameters
  • Argument Clinic: Fix signature of optional positional-only arguments
  • _struct module
  • DONE: print() function. TODO: convert to Argument Clinic (need *args).
  • Search for Argument Clinic open issues
• Better bytecode/AST?
  • Issue #1346238: A constant folding optimization pass for the AST
  • Issue #11549: Build-out an AST optimizer, moving some functionality out of the peephole optimizer
• Split PyGC_Head from object (ML thread)
  • sizeof 1-tuple becomes (1 (pointer to gc head) + 3 (PyVarObject) + 1) words from (3 (gc head) + 3 + 1) words.
• Embed some tuples into code object.
  • When co_consts is (None,), code object uses 8 (or 6 if above optimization is land) words for the tuple and the pointer to it. It can be 2 words (length and one PyObject*).
  • It may reduce RAM usage and improve cache utilization.
• Optimize option for stripping __annotation__.
  • Reduces one dict for each (annotated) functions.
  • -O3 may be OK, but indivisual optimization flag (e.g. -Odocstring) would be better. It affects PEP 488.
• Interned-key only dict: Most name lookup uses interned string. If dict contains only interned keys only, lookup can see only pointer, and hash can be dropped from dict entries. This can reduce memory usage and cache utilization of namespece dicts.
• Global freepool: Many types has it’s own freepool. Sharing freepool can increase memory and cache efficiency. Add PyMem_FastFree(void* ptr, size_t size) to store memory block to freepool, and PyMem_Malloc can check global freepool first.