On Tue, Nov 20, 2018 at 6:05 PM Glenn Linderman <v+pyt...@g.nevcal.com> wrote: > > On 11/20/2018 2:17 PM, Victor Stinner wrote: >> IMHO performance and hiding implementation details are exclusive. You >> should either use the C API with impl. details for best performances, >> or use a "limited" C API for best compatibility. > > The "limited" C API concept would seem to be quite sufficient for extensions > that want to extend Python functionality to include new system calls, etc. > (pywin32, pyMIDI, pySide, etc.) whereas the numpy and decimal might want best > performance.
To make things more complicated: numpy and decimal are in a category of modules where if you want them to perform well on JIT-based VMs, then there's no possible C API that can achieve that. To get the benefits of a JIT on code using numpy or decimal, the JIT has to be able to see into their internals to do inlining etc., which means they can't be written in C at all [1], at which point the C API becomes irrelevant. It's not clear to me how this affects any of the discussion in CPython, since supporting JITs might not be part of the goal of a new C API, and I'm not sure how many packages fall between the numpy/decimal side and the pure-ffi side. -n [1] Well, there's also the option of teaching your Python JIT to handle LLVM bitcode as a source language, which is the approach that Graal is experimenting with. It seems completely wacky to me to hope you could write a C API emulation layer like PyPy's cpyext, and compile that + C extension code to LLVM bitcode, translate the LLVM bitcode to JVM bytecode, inline the whole mess into your Python JIT, and then fold everything away to produce something reasonable. But I could be wrong, and Oracle is throwing a lot of money at Graal so I guess we'll find out. -- Nathaniel J. Smith -- https://vorpus.org _______________________________________________ Python-Dev mailing list Python-Dev@python.org https://mail.python.org/mailman/listinfo/python-dev Unsubscribe: https://mail.python.org/mailman/options/python-dev/archive%40mail-archive.com
