Each thread specializes a thread-local copy of the bytecode, created on the first RESUME, in free-threaded builds. All copies of the bytecode for a code object are stored in the co_tlbc array on the code object. Threads reserve a globally unique index identifying its copy of the bytecode in all co_tlbc arrays at thread creation and release the index at thread destruction. The first entry in every co_tlbc array always points to the "main" copy of the bytecode that is stored at the end of the code object. This ensures that no bytecode is copied for programs that do not use threads.
Thread-local bytecode can be disabled at runtime by providing either -X tlbc=0 or PYTHON_TLBC=0. Disabling thread-local bytecode also disables specialization.
Concurrent modifications to the bytecode made by the specializing interpreter and instrumentation use atomics, with specialization taking care not to overwrite an instruction that was instrumented concurrently.
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.
The free-threaded build partially stores heap type reference counts in
distributed manner in per-thread arrays. This avoids reference count
contention when creating or destroying instances.
Co-authored-by: Ken Jin <kenjin@python.org>
These helpers make it easier to customize and inspect the config used to initialize interpreters. This is especially valuable in our tests. I found inspiration from the PyConfig API for the PyInterpreterConfig dict conversion stuff. As part of this PR I've also added a bunch of tests.
I added it quite a while ago as a strategy for managing interpreter lifetimes relative to the PEP 554 (now 734) implementation. Relatively recently I refactored that implementation to no longer rely on InterpreterID objects. Thus now I'm removing it.
Keep Tools/build/deepfreeze.py around (we may repurpose it for deepfreezing non-code objects),
and keep basic "clean" targets that remove the output of former deep-freeze activities,
to keep the build directories of current devs clean.
This adds a safe memory reclamation scheme based on FreeBSD's "GUS" and
quiescent state based reclamation (QSBR). The API provides a mechanism
for callers to detect when it is safe to free memory that may be
concurrently accessed by readers.
Biased reference counting maintains two refcount fields in each object:
`ob_ref_local` and `ob_ref_shared`. The true refcount is the sum of these two
fields. In some cases, when refcounting operations are split across threads,
the ob_ref_shared field can be negative (although the total refcount must be
at least zero). In this case, the thread that decremented the refcount
requests that the owning thread give up ownership and merge the refcount
fields.
Add an option (--enable-experimental-jit for configure-based builds
or --experimental-jit for PCbuild-based ones) to build an
*experimental* just-in-time compiler, based on copy-and-patch (https://fredrikbk.com/publications/copy-and-patch.pdf).
See Tools/jit/README.md for more information on how to install the required build-time tooling.
* gh-112529: Implement GC for free-threaded builds
This implements a mark and sweep GC for the free-threaded builds of
CPython. The implementation relies on mimalloc to find GC tracked
objects (i.e., "containers").
This splits part of Modules/gcmodule.c of into Python/gc.c, which
now contains the core garbage collection implementation. The Python
module remain in the Modules/gcmodule.c file.
This ensures the source directory is not modified at build time, and different builds (e.g. different versions or GIL vs no-GIL) do not have conflicts.
Critical sections are helpers to replace the global interpreter lock
with finer grained locking. They provide similar guarantees to the GIL
and avoid the deadlock risk that plain locking involves. Critical
sections are implicitly ended whenever the GIL would be released. They
are resumed when the GIL would be acquired. Nested critical sections
behave as if the sections were interleaved.
- There is no longer a separate Python/executor.c file.
- Conventions in Python/bytecodes.c are slightly different -- don't use `goto error`,
you must use `GOTO_ERROR(error)` (same for others like `unused_local_error`).
- The `TIER_ONE` and `TIER_TWO` symbols are only valid in the generated (.c.h) files.
- In Lib/test/support/__init__.py, `Py_C_RECURSION_LIMIT` is imported from `_testcapi`.
- On Windows, in debug mode, stack allocation grows from 8MiB to 12MiB.
- **Beware!** This changes the env vars to enable uops and their debugging
to `PYTHON_UOPS` and `PYTHON_LLTRACE`.
This is partly to clear this stuff out of pystate.c, but also in preparation for moving some code out of _xxsubinterpretersmodule.c. This change also moves this stuff to the internal API (new: Include/internal/pycore_crossinterp.h). @vstinner did this previously and I undid it. Now I'm re-doing it. :/
* Add mimalloc v2.12
Modified src/alloc.c to remove include of alloc-override.c and not
compile new handler.
Did not include the following files:
- include/mimalloc-new-delete.h
- include/mimalloc-override.h
- src/alloc-override-osx.c
- src/alloc-override.c
- src/static.c
- src/region.c
mimalloc is thread safe and shares a single heap across all runtimes,
therefore finalization and getting global allocated blocks across all
runtimes is different.
* mimalloc: minimal changes for use in Python:
- remove debug spam for freeing large allocations
- use same bytes (0xDD) for freed allocations in CPython and mimalloc
This is important for the test_capi debug memory tests
* Don't export mimalloc symbol in libpython.
* Enable mimalloc as Python allocator option.
* Add mimalloc MIT license.
* Log mimalloc in Lib/test/pythoninfo.py.
* Document new mimalloc support.
* Use macro defs for exports as done in:
https://github.com/python/cpython/pull/31164/
Co-authored-by: Sam Gross <colesbury@gmail.com>
Co-authored-by: Christian Heimes <christian@python.org>
Co-authored-by: Victor Stinner <vstinner@python.org>
* The lexer, which include the actual lexeme producing logic, goes into
the `lexer` directory.
* The wrappers, one wrapper per input mode (file, string, utf-8, and
readline), go into the `tokenizer` directory and include logic for
creating a lexer instance and managing the buffer for different modes.
---------
Co-authored-by: Pablo Galindo <pablogsal@gmail.com>
Co-authored-by: blurb-it[bot] <43283697+blurb-it[bot]@users.noreply.github.com>
This implements PEP 695, Type Parameter Syntax. It adds support for:
- Generic functions (def func[T](): ...)
- Generic classes (class X[T](): ...)
- Type aliases (type X = ...)
- New scoping when the new syntax is used within a class body
- Compiler and interpreter changes to support the new syntax and scoping rules
Co-authored-by: Marc Mueller <30130371+cdce8p@users.noreply.github.com>
Co-authored-by: Eric Traut <eric@traut.com>
Co-authored-by: Larry Hastings <larry@hastings.org>
Co-authored-by: Alex Waygood <Alex.Waygood@Gmail.com>
* The majority of the monitoring code is in instrumentation.c
* The new instrumentation bytecodes are in bytecodes.c
* legacy_tracing.c adapts the new API to the old sys.setrace and sys.setprofile APIs
⚠️⚠️ Note for reviewers, hackers and fellow systems/low-level/compiler engineers ⚠️⚠️
If you have a lot of experience with this kind of shenanigans and want to improve the **first** version, **please make a PR against my branch** or **reach out by email** or **suggest code changes directly on GitHub**.
If you have any **refinements or optimizations** please, wait until the first version is merged before starting hacking or proposing those so we can keep this PR productive.
This defines VPATH differently in PGO instrumentation builds, to account for a different default output directory. It also adds sys._vpath on Windows to make the value available to sysconfig so that it can be used in tests.
The getpath.py file is frozen at build time and executed as code over a namespace. It is never imported, nor is it meant to be importable or reusable. However, it should be easier to read, modify, and patch than the previous code.
This commit attempts to preserve every previously tested quirk, but these may be changed in the future to better align platforms.
Implement changes to build with deep-frozen modules on Windows.
Note that we now require Python 3.10 as the "bootstrap" or "host" Python.
This causes a modest startup speed (around 7%) on Windows.
mpage
Sam Gross
Irit Katriel
Pablo Galindo Salgado
Eric Snow
Guido van Rossum
Mark Shannon
Brandt Bucher
Donghee Na
Itamar Oren
Steve Dower
Dino Viehland
Riccardo Ghetta
Lysandros Nikolaou
Ken Jin
Jelle Zijlstra
Victor Stinner
Charlie Zhao
Aivars Kalvāns
Kumar Aditya
neonene
Christian Heimes
Kumar Aditya