Author: Armin Rigo <ar...@tunes.org> Branch: extradoc Changeset: r5180:a4fb1f479cb1 Date: 2014-04-04 12:25 +0200 http://bitbucket.org/pypy/extradoc/changeset/a4fb1f479cb1/
Log: Rewrite this section diff --git a/planning/tmdonate2.txt b/planning/tmdonate2.txt --- a/planning/tmdonate2.txt +++ b/planning/tmdonate2.txt @@ -211,25 +211,36 @@ rest of the program should work without changes. -Other non-Linux platforms -------------------------- +Other platforms than the x86-64 Linux +------------------------------------- -The current work relies heavily on Linux-, clang-, and 64-bit only -features. We believe it is a suitable restriction: a lot of multi- and -many-core servers commonly available are nowadays x86-64 machines -running Linux. (If PyPy gets a 64-bit ARMv8 JIT backend, adapting it -for STM should be easy). Nevertheless, non-Linux solutions appear to be -possible as well. OS/X (and likely the various BSDs) seems to handle -``mmap()`` better than Linux does, and can remap individual pages of an -existing mapping to various pages without hitting a limit of 65536 like -Linux. Windows might also have a way, although we didn't measure yet; -but the first issue with Windows would be to support Win64, which the -regular PyPy doesn't. +The first thing to note is that the current solution depends on having a +huge address space available. If it were to be ported to any 32-bit +architecture, the limitation to 2GB or 4GB of address space would become +very restrictive: the way it works right now would further divide this +limit by N+1, where N is the number of segments. It might be possible +to create partially different memory views for multiple threads that +each access the same range of addresses; this would require extensions +that are very OS-specific. We didn't investigate so far. + +The current version, which thus only works on 64-bit, still relies +heavily on Linux- and clang-only features. We believe it is a suitable +restriction: a lot of multi- and many-core servers commonly available +are nowadays x86-64 machines running Linux. Nevertheless, non-Linux +solutions appear to be possible as well. OS/X (and likely the various +BSDs) seems to handle ``mmap()`` better than Linux does, and can remap +individual pages of an existing mapping to various pages without hitting +a limit of 65536 like Linux. Windows might also have a way, although we +didn't measure yet; but the first issue with Windows would be to support +Win64, which the regular PyPy doesn't. We will likely explore the OS/X way (as well as the Windows way if Win64 support grows in PyPy), but this is not included in the scope of this proposal. +It might be possible to adapt the work done on x86-64 to the 64-bit +ARMv8 as well, but we didn't investigate so far. + More readings ------------- _______________________________________________ pypy-commit mailing list pypy-commit@python.org https://mail.python.org/mailman/listinfo/pypy-commit
