cpython/Include/pyatomic.h

#ifndef Py_ATOMIC_H
#define Py_ATOMIC_H
#ifdef __cplusplus
extern "C" {
#endif

#ifndef Py_LIMITED_API
#  define Py_CPYTHON_ATOMIC_H
#  include "cpython/pyatomic.h"
#  undef Py_CPYTHON_ATOMIC_H
#endif

#ifdef __cplusplus
}
#endif
#endif  /* !Py_ATOMIC_H */
gh-108724: Add PyMutex and _PyParkingLot APIs (gh-109344) 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> 2023-09-19 11:54:29 -04:00			`#ifndef Py_ATOMIC_H`
			`#define Py_ATOMIC_H`
			`#ifdef __cplusplus`
			`extern "C" {`
			`#endif`

			`#ifndef Py_LIMITED_API`
			`# define Py_CPYTHON_ATOMIC_H`
			`# include "cpython/pyatomic.h"`
			`# undef Py_CPYTHON_ATOMIC_H`
			`#endif`

			`#ifdef __cplusplus`
			`}`
			`#endif`
			`#endif /* !Py_ATOMIC_H */`