New submission from Neil Schemenauer <nas-pyt...@arctrix.com>:
Given this feedback: https://github.com/python/cpython/pull/14474/files#r725488766 it is perhaps not so safe to assume that only the lower 48 bits of virtual addresses are significant. I had the idea that Go made similar assumptions but now I'm not sure it does. There is also a comment in this article about 5-level page tables in Linux: https://lwn.net/Articles/717293/ https://lwn.net/Articles/717300/ I.e. that Linux does not allocate virtual address space above 47-bit by default. Setting ADDRESS_BITS to 64 is safer and the performance impact seems small. The virtual memory size of a small Python process goes up a little. Resident set size doesn't significantly change. I think the pyperformance changes are just noise. The pyperformance attached file shows the 3.10 branch with ADDRESS_BITS set to 48 and to 64. ---------- assignee: methane files: pyperf-compare-addr-64.txt messages: 404317 nosy: methane, nascheme priority: normal severity: normal stage: patch review status: open title: Set ADDRESS_BITS to 64 for obmalloc radix tree Added file: https://bugs.python.org/file50370/pyperf-compare-addr-64.txt _______________________________________ Python tracker <rep...@bugs.python.org> <https://bugs.python.org/issue45526> _______________________________________ _______________________________________________ Python-bugs-list mailing list Unsubscribe: https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
