Hi Greg You wrote:
On 19/06/20 9:28 am, Steven D'Aprano wrote: > > I know very little about how this works except a vague rule of thumb > > that in the 21st century memory locality is king. If you want code to be > > fast, keep it close together, not spread out. > > Python objects are already scattered all over memory, and a > function already consists of several objects -- the function > object itself, a dict, a code object, lists of argument and > local variable names, etc. I doubt whether the suggested > change would make locality noticeably worse. > I like this response. I'd also add a link to https://en.wikipedia.org/wiki/Non-uniform_memory_access NUMA arises because quick memory is expensive, with CPU registers the quickest of all, and revolving hard disks (and then tape) at the slow end, and RAM and SSD somewhere in the middle. In addition, modern CPUs are multicore, each with its own registers and cache. Optimising such systems is difficult, particularly as what's best depends on the data being processed. One part of testing would be to provide guidance as to the situations, in which permanent code objects would bring some benefit. Even with UMA (no caches etc), there could be the benefit of reduced use of memory (as no longer keeping two almost identical copies of the same object). An aside. Precisely with UMA there is no benefit to locality. I'd say getting as much of the busy code as you can into the CPU caches will bring benefits. Unix introduces shared objects, and on Linux C-coded extensions are available as shared objects. >>> import lxml.etree as etree >>> etree <module 'lxml.etree' from '[...] etree.cpython-36m-x86_64-linux-gnu.so'> Summary: The proposal is that the Python interpreter be extended, so that it can access pure Python code objects that are part of a Unix shared object. I hope this helps. Thank you, Greg and Steve, for your interest and contributions. -- Jonathan
_______________________________________________ Python-ideas mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3/lists/python-ideas.python.org/ Message archived at https://mail.python.org/archives/list/[email protected]/message/T5F3IJTKRC2PN27EPVSKRP2WW53HITRB/ Code of Conduct: http://python.org/psf/codeofconduct/
