* gh-117151: increase default buffer size of shutil.copyfileobj() to 256k.
it was set to 16k in the 1990s.
it was raised to 64k in 2019. the discussion at the time mentioned another 5% improvement by raising to 128k and settled for a very conservative setting.
it's 2024 now, I think it should be revisited to match modern hardware. I am measuring 0-15% performance improvement when raising to 256k on various types of disk. there is no downside as far as I can tell.
this function is only intended for sequential copy of full files (or file like objects). it's the typical use case that benefits from larger operations.
for reference, I came across this function while trying to profile pip that is using it to copy files when installing python packages.
* add news
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Co-authored-by: rmorotti <romain.morotti@man.com>
Cache in C PEG-generator reworked:
we save artificial rules in cache by Node string representation as a key instead of Node object itself.
As a result total count of artificial rules in parsers.c is lowered from 283 to 170.
More natural number ordering is used for the names of artificial rules.
Auxiliary method CCallMakerVisitor._generate_artificial_rule_call is added.
Its purpose is abstracting work with artificial rules cache.
Explicit using of "is_repeat1" kwarg is added to visit_Repeat0 and visit_Repeat1 methods.
Its slightly improve code readabitily.
Instead of surprise crashes and memory corruption, we now hang threads that attempt to re-enter the Python interpreter after Python runtime finalization has started. These are typically daemon threads (our long standing mis-feature) but could also be threads spawned by extension modules that then try to call into Python. This marks the `PyThread_exit_thread` public C API as deprecated as there is no plausible safe way to accomplish that on any supported platform in the face of things like C++ code with finalizers anywhere on a thread's stack. Doing this was the least bad option.
Co-authored-by: Gregory P. Smith <greg@krypto.org>
Fix the incorrect use of `os.open()` result as a context manager,
while it is actually a numeric file descriptor.
I have missed the problem, because in the original version the
`os.open()` call would always fail, and I failed to test the final
version in all possible scenarios properly.
This is actually an upstream problem in curses, and has been reported
to them already:
https://lists.gnu.org/archive/html/bug-ncurses/2024-09/msg00101.html
This is a nice workaround in the meantime to prevent the segfault.
Co-authored-by: Bénédikt Tran <10796600+picnixz@users.noreply.github.com>
Previously when executing ``test_functattrs.test___builtins__`` directly, it failed because the fact, that ``__builtins__`` is refers to the built-in module ``builtins`` while it's expects a ``__builtins__.__dict__``. But when this test is being run from another module, then ``__builtins__`` is refers to ``builtins.__dict__``. Now this part of the behaviour is covered.
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Co-authored-by: Victor Stinner <vstinner@python.org>
Previously, formatting help output or error message for positional argument
with a tuple metavar raised exception.
Co-authored-by: Cyker Way <cykerway@gmail.com>
It can now have one of three forms:
* basename(argv0) -- for simple scripts
* python arv0 -- for directories, ZIP files, etc
* python -m module -- for imported modules
Co-authored-by: Alyssa Coghlan <ncoghlan@gmail.com>
Currently, we only use per-thread reference counting for heap type objects and
the naming reflects that. We will extend it to a few additional types in an
upcoming change to avoid scaling bottlenecks when creating nested functions.
Rename some of the files and functions in preparation for this change.
Victor Stinner
Donghee Na
Tian Gao
Adam Turner
morotti
Irit Katriel
isaacjones99
Nice Zombies
Felix Fontein
Christian Clauss
Bénédikt Tran
Pablo Galindo Salgado
Raymond Hettinger
efimov-mikhail
Tomas R
Thomas Grainger
Brandt Bucher
Diego Russo
Ken Jin
Jeremy Maitin-Shepard
Michał Górny
Peter Bierma
Serhiy Storchaka
Mark Byrne
Savannah Ostrowski
Taneli Hukkinen
Gregory P. Smith
Sam Gross