PyMutex is a one byte lock with fast, inlineable lock and unlock functions for the common uncontended case. The design is based on WebKit's WTF::Lock.
PyMutex is built using the _PyParkingLot APIs, which provides a cross-platform futex-like API (based on WebKit's WTF::ParkingLot). This internal API will be used for building other synchronization primitives used to implement PEP 703, such as one-time initialization and events.
This also includes tests and a mini benchmark in Tools/lockbench/lockbench.py to compare with the existing PyThread_type_lock.
Uncontended acquisition + release:
* Linux (x86-64): PyMutex: 11 ns, PyThread_type_lock: 44 ns
* macOS (arm64): PyMutex: 13 ns, PyThread_type_lock: 18 ns
* Windows (x86-64): PyMutex: 13 ns, PyThread_type_lock: 38 ns
PR Overview:
The primary purpose of this PR is to implement PyMutex, but there are a number of support pieces (described below).
* PyMutex: A 1-byte lock that doesn't require memory allocation to initialize and is generally faster than the existing PyThread_type_lock. The API is internal only for now.
* _PyParking_Lot: A futex-like API based on the API of the same name in WebKit. Used to implement PyMutex.
* _PyRawMutex: A word sized lock used to implement _PyParking_Lot.
* PyEvent: A one time event. This was used a bunch in the "nogil" fork and is useful for testing the PyMutex implementation, so I've included it as part of the PR.
* pycore_llist.h: Defines common operations on doubly-linked list. Not strictly necessary (could do the list operations manually), but they come up frequently in the "nogil" fork. ( Similar to https://man.freebsd.org/cgi/man.cgi?queue)
---------
Co-authored-by: Eric Snow <ericsnowcurrently@gmail.com>
This makes the internal representation in the code generator simpler: there's a list of ops, and a list of macros, and there's no special-casing needed for ops that aren't macros. (There's now special-casing for ops that are also macros, but that's simpler.)
Builtin functions and methods that have non-representable signatures today
will have representable signatures yesterday, and they will become unusable
for testing this feature.
So we need to add special functions and methods to the _testcapi module
that always have non-representable signatures.
I must have overlooked this when refactoring the code generator.
The Tier 1 interpreter contained a few silly things like
```
goto resume_frame;
STACK_SHRINK(1);
```
(and other variations, some where the unconditional `goto` was hidden in a macro).
* Rename SAVE_IP to _SET_IP
* Rename EXIT_TRACE to _EXIT_TRACE
* Rename SAVE_CURRENT_IP to _SAVE_CURRENT_IP
* Rename INSERT to _INSERT (This is for Ken Jin's abstract interpreter)
* Rename IS_NONE to _IS_NONE
* Rename JUMP_TO_TOP to _JUMP_TO_TOP
This adds a 16-bit inline cache entry to the conditional branch instructions POP_JUMP_IF_{FALSE,TRUE,NONE,NOT_NONE} and their instrumented variants, which is used to keep track of the branch direction.
Each time we encounter these instructions we shift the cache entry left by one and set the bottom bit to whether we jumped.
Then when it's time to translate such a branch to Tier 2 uops, we use the bit count from the cache entry to decided whether to continue translating the "didn't jump" branch or the "jumped" branch.
The counter is initialized to a pattern of alternating ones and zeros to avoid bias.
The .pyc file magic number is updated. There's a new test, some fixes for existing tests, and a few miscellaneous cleanups.
Fix a race condition in "make regen-all". The deepfreeze.c source and
files generated by Argument Clinic are now generated or updated
before generating "global objects". Previously, some identifiers may
miss depending on the order in which these files were generated.
* "make regen-global-objects": Make sure that deepfreeze.c is
generated and up to date, and always run "make clinic".
* "make clinic" no longer runs generate_global_objects.py script.
* "make regen-deepfreeze" now only updates deepfreeze.c (C file).
It doesn't build deepfreeze.o (object) anymore.
* Remove misleading messages in "make regen-global-objects" and
"make clinic". They are now outdated, these commands are now
safe to use.
* Document generates files in Doc/using/configure.rst.
Co-authored-by: Erlend E. Aasland <erlend@python.org>
Output with one wheel:
```
❯ GITHUB_ACTIONS=true ./Tools/build/verify_ensurepip_wheels.py
Verifying checksum for /Volumes/RAMDisk/cpython/Lib/ensurepip/_bundled/pip-23.2.1-py3-none-any.whl.
Expected digest: 7ccf472345f20d35bdc9d1841ff5f313260c2c33fe417f48c30ac46cccabf5be
Actual digest: 7ccf472345f20d35bdc9d1841ff5f313260c2c33fe417f48c30ac46cccabf5be
::notice file=/Volumes/RAMDisk/cpython/Lib/ensurepip/_bundled/pip-23.2.1-py3-none-any.whl::Successfully verified the checksum of the pip wheel.
```
Output with two wheels:
```
❯ GITHUB_ACTIONS=true ./Tools/build/verify_ensurepip_wheels.py
::error file=/Volumes/RAMDisk/cpython/Lib/ensurepip/_bundled/pip-22.0.4-py3-none-any.whl::Found more than one wheel for package pip.
::error file=/Volumes/RAMDisk/cpython/Lib/ensurepip/_bundled/pip-23.2.1-py3-none-any.whl::Found more than one wheel for package pip.
```
Output without wheels:
```
❯ GITHUB_ACTIONS=true ./Tools/build/verify_ensurepip_wheels.py
::error file=::Could not find a pip wheel on disk.
```
Argument Clinic now only includes pycore_gc.h if PyGC_Head is needed,
and only includes pycore_runtime.h if _Py_ID() is needed.
* Add 'condition' optional argument to Clinic.add_include().
* deprecate_keyword_use() includes pycore_runtime.h when using
the _PyID() function.
* Fix rendering of includes: comments start at the column 35.
* Mark PC/clinic/_wmimodule.cpp.h and
"Objects/stringlib/clinic/*.h.h" header files as generated in
.gitattributes.
Effects:
* 42 header files generated by AC no longer include the internal C
API, instead of 4 header files before. For example,
Modules/clinic/_abc.c.h no longer includes the internal C API.
* Fix _testclinic_depr.c.h: it now always includes pycore_runtime.h
to get _Py_ID().
Also remove NOP instructions.
The "stubs" are not optimized in this fashion (their SAVE_IP should always be preserved since it's where to jump next, and they don't contain NOPs by their nature).
Move these private functions to the internal C API
(pycore_abstract.h):
* _Py_convert_optional_to_ssize_t()
* _PyNumber_Index()
Argument Clinic now emits #include "pycore_abstract.h" when these
functions are used.
The parser of the c-analyzer tool now uses a list of files which use
the limited C API, rather than a list of files using the internal C
API.
Move the private _PyLong converter functions to the internal C API
* _PyLong_FileDescriptor_Converter(): moved to pycore_fileutils.h
* _PyLong_Size_t_Converter(): moved to pycore_long.h
Argument Clinic now emits includes for pycore_fileutils.h and
pycore_long.h when these functions are used.
Move these private functions to the internal C API (pycore_long.h):
* _PyLong_UnsignedInt_Converter()
* _PyLong_UnsignedLongLong_Converter()
* _PyLong_UnsignedLong_Converter()
* _PyLong_UnsignedShort_Converter()
Argument Clinic now emits #include "pycore_long.h" when these
functions are used.
* Add Clinic.add_include() method
* Add CConverter.include and CConverter.add_include()
* Printer.print_block() gets a second parameter: clinic.
* Remove duplicated declaration of "clinic" global variable.
Argument Clinic now has a partial support of the
Limited API:
* Add --limited option to clinic.c.
* Add '_testclinic_limited' extension which is built with
the limited C API version 3.13.
* For now, hardcode in clinic.py that "_testclinic_limited.c" targets
the limited C API.
Instead of using `GO_TO_INSTRUCTION(CALL_PY_EXACT_ARGS)` we just add the macro elements of the latter to the macro for the former. This requires lengthening the uops array in struct opcode_macro_expansion. (It also required changes to stacking.py that were merged already.)
Victor Stinner