Mercurial > hg
view mercurial/pythoncapi_compat.h @ 48068:bf8837e3d7ce
dirstate: Remove the flat Rust DirstateMap implementation
Before this changeset we had two Rust implementations of `DirstateMap`.
This removes the "flat" DirstateMap so that the "tree" DirstateMap is always
used when Rust enabled. This simplifies the code a lot, and will enable
(in the next changeset) further removal of a trait abstraction.
This is a performance regression when:
* Rust is enabled, and
* The repository uses the legacy dirstate-v1 file format, and
* For `hg status`, unknown files are not listed (such as with `-mard`)
The regression is about 100 milliseconds for `hg status -mard` on a
semi-large repository (mozilla-central), from ~320ms to ~420ms.
We deem this to be small enough to be worth it.
The new dirstate-v2 is still experimental at this point, but we aim to
stabilize it (though not yet enable it by default for new repositories)
in Mercurial 6.0. Eventually, upgrating repositories to dirsate-v2 will
eliminate this regression (and enable other performance improvements).
# Background
The flat DirstateMap was introduced with the first Rust implementation of the
status algorithm. It works similarly to the previous Python + C one, with a
single `HashMap` that associates file paths to a `DirstateEntry` (where Python
has a dict).
We later added the tree DirstateMap where the root of the tree contains nodes
for files and directories that are directly at the root of the repository,
and nodes for directories can contain child nodes representing the files and
directly that *they* contain directly. The shape of this tree mirrors that of
the working directory in the filesystem. This enables the status algorithm to
traverse this tree in tandem with traversing the filesystem tree, which in
turns enables a more efficient algorithm.
Furthermore, the new dirstate-v2 file format is also based on a tree of the
same shape. The tree DirstateMap can access a dirstate-v2 file without parsing
it: binary data in a single large (possibly memory-mapped) bytes buffer is
traversed on demand. This allows `DirstateMap` creation to take `O(1)` time.
(Mutation works by creating new in-memory nodes with copy-on-write semantics,
and serialization is append-mostly.)
The tradeoff is that for "legacy" repositories that use the dirstate-v1 file
format, parsing that file into a tree DirstateMap takes more time. Profiling
shows that this time is dominated by `HashMap`. For a dirstate containing `F`
files with an average `D` directory depth, the flat DirstateMap does parsing
in `O(F)` number of HashMap operations but the tree DirstateMap in `O(F × D)`
operations, since each node has its own HashMap containing its child nodes.
This slower costs ~140ms on an old snapshot of mozilla-central, and ~80ms
on an old snapshot of the Netbeans repository.
The status algorithm is faster, but with `-mard` (when not listing unknown
files) it is typically not faster *enough* to compensate the slower parsing.
Both Rust implementations are always faster than the Python + C implementation
# Benchmark results
All benchmarks are run on changeset 98c0408324e6, with repositories that use
the dirstate-v1 file format, on a server with 4 CPU cores and 4 CPU threads
(no HyperThreading).
`hg status` benchmarks show wall clock times of the entire command as the
average and standard deviation of serveral runs, collected by
https://github.com/sharkdp/hyperfine and reformated.
Parsing benchmarks are wall clock time of the Rust function that converts a
bytes buffer of the dirstate file into the `DirstateMap` data structure as
used by the status algorithm. A single run each, collected by running
`hg status` this environment variable:
RUST_LOG=hg::dirstate::dirstate_map=trace,hg::dirstate_tree::dirstate_map=trace
Benchmark 1: Rust flat DirstateMap → Rust tree DirstateMap
hg status
mozilla-clean 562.3 ms ± 2.0 ms → 462.5 ms ± 0.6 ms 1.22 ± 0.00 times faster
mozilla-dirty 859.6 ms ± 2.2 ms → 719.5 ms ± 3.2 ms 1.19 ± 0.01 times faster
mozilla-ignored 558.2 ms ± 3.0 ms → 457.9 ms ± 2.9 ms 1.22 ± 0.01 times faster
mozilla-unknowns 859.4 ms ± 5.7 ms → 716.0 ms ± 4.7 ms 1.20 ± 0.01 times faster
netbeans-clean 336.5 ms ± 0.9 ms → 339.5 ms ± 0.4 ms 0.99 ± 0.00 times faster
netbeans-dirty 491.4 ms ± 1.6 ms → 475.1 ms ± 1.2 ms 1.03 ± 0.00 times faster
netbeans-ignored 343.7 ms ± 1.0 ms → 347.8 ms ± 0.4 ms 0.99 ± 0.00 times faster
netbeans-unknowns 484.3 ms ± 1.0 ms → 466.0 ms ± 1.2 ms 1.04 ± 0.00 times faster
hg status -mard
mozilla-clean 317.3 ms ± 0.6 ms → 422.5 ms ± 1.2 ms 0.75 ± 0.00 times faster
mozilla-dirty 315.4 ms ± 0.6 ms → 417.7 ms ± 1.1 ms 0.76 ± 0.00 times faster
mozilla-ignored 314.6 ms ± 0.6 ms → 417.4 ms ± 1.0 ms 0.75 ± 0.00 times faster
mozilla-unknowns 312.9 ms ± 0.9 ms → 417.3 ms ± 1.6 ms 0.75 ± 0.00 times faster
netbeans-clean 212.0 ms ± 0.6 ms → 283.6 ms ± 0.8 ms 0.75 ± 0.00 times faster
netbeans-dirty 211.4 ms ± 1.0 ms → 283.4 ms ± 1.6 ms 0.75 ± 0.01 times faster
netbeans-ignored 211.4 ms ± 0.9 ms → 283.9 ms ± 0.8 ms 0.74 ± 0.01 times faster
netbeans-unknowns 211.1 ms ± 0.6 ms → 283.4 ms ± 1.0 ms 0.74 ± 0.00 times faster
Parsing
mozilla-clean 38.4ms → 177.6ms
mozilla-dirty 38.8ms → 177.0ms
mozilla-ignored 38.8ms → 178.0ms
mozilla-unknowns 38.7ms → 176.9ms
netbeans-clean 16.5ms → 97.3ms
netbeans-dirty 16.5ms → 98.4ms
netbeans-ignored 16.9ms → 97.4ms
netbeans-unknowns 16.9ms → 96.3ms
Benchmark 2: Python + C dirstatemap → Rust tree DirstateMap
hg status
mozilla-clean 1261.0 ms ± 3.6 ms → 461.1 ms ± 0.5 ms 2.73 ± 0.00 times faster
mozilla-dirty 2293.4 ms ± 9.1 ms → 719.6 ms ± 3.6 ms 3.19 ± 0.01 times faster
mozilla-ignored 1240.4 ms ± 2.3 ms → 457.7 ms ± 1.9 ms 2.71 ± 0.00 times faster
mozilla-unknowns 2283.3 ms ± 9.0 ms → 719.7 ms ± 3.8 ms 3.17 ± 0.01 times faster
netbeans-clean 879.7 ms ± 3.5 ms → 339.9 ms ± 0.5 ms 2.59 ± 0.00 times faster
netbeans-dirty 1257.3 ms ± 4.7 ms → 474.6 ms ± 1.6 ms 2.65 ± 0.01 times faster
netbeans-ignored 943.9 ms ± 1.9 ms → 347.3 ms ± 1.1 ms 2.72 ± 0.00 times faster
netbeans-unknowns 1188.1 ms ± 5.0 ms → 465.2 ms ± 2.3 ms 2.55 ± 0.01 times faster
hg status -mard
mozilla-clean 903.2 ms ± 3.6 ms → 423.4 ms ± 2.2 ms 2.13 ± 0.01 times faster
mozilla-dirty 884.6 ms ± 4.5 ms → 417.3 ms ± 1.4 ms 2.12 ± 0.01 times faster
mozilla-ignored 881.9 ms ± 1.3 ms → 417.3 ms ± 0.8 ms 2.11 ± 0.00 times faster
mozilla-unknowns 878.5 ms ± 1.9 ms → 416.4 ms ± 0.9 ms 2.11 ± 0.00 times faster
netbeans-clean 434.9 ms ± 1.8 ms → 284.0 ms ± 0.8 ms 1.53 ± 0.01 times faster
netbeans-dirty 434.1 ms ± 0.8 ms → 283.1 ms ± 0.8 ms 1.53 ± 0.00 times faster
netbeans-ignored 431.7 ms ± 1.1 ms → 283.6 ms ± 1.8 ms 1.52 ± 0.01 times faster
netbeans-unknowns 433.0 ms ± 1.3 ms → 283.5 ms ± 0.7 ms 1.53 ± 0.00 times faster
Differential Revision: https://phab.mercurial-scm.org/D11516
author | Simon Sapin <simon.sapin@octobus.net> |
---|---|
date | Mon, 27 Sep 2021 12:09:15 +0200 |
parents | 38b9a63d3a13 |
children |
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// Header file providing new functions of the Python C API to old Python // versions. // // File distributed under the MIT license. // // Homepage: // https://github.com/pythoncapi/pythoncapi_compat // // Latest version: // https://raw.githubusercontent.com/pythoncapi/pythoncapi_compat/master/pythoncapi_compat.h #ifndef PYTHONCAPI_COMPAT #define PYTHONCAPI_COMPAT #ifdef __cplusplus extern "C" { #endif #include <Python.h> #include "frameobject.h" // PyFrameObject, PyFrame_GetBack() /* VC 2008 doesn't know about the inline keyword. */ #if defined(_MSC_VER) && _MSC_VER < 1900 #define inline __forceinline #endif // Cast argument to PyObject* type. #ifndef _PyObject_CAST # define _PyObject_CAST(op) ((PyObject*)(op)) #endif // bpo-42262 added Py_NewRef() to Python 3.10.0a3 #if PY_VERSION_HEX < 0x030a00A3 && !defined(Py_NewRef) static inline PyObject* _Py_NewRef(PyObject *obj) { Py_INCREF(obj); return obj; } #define Py_NewRef(obj) _Py_NewRef(_PyObject_CAST(obj)) #endif // bpo-42262 added Py_XNewRef() to Python 3.10.0a3 #if PY_VERSION_HEX < 0x030a00A3 && !defined(Py_XNewRef) static inline PyObject* _Py_XNewRef(PyObject *obj) { Py_XINCREF(obj); return obj; } #define Py_XNewRef(obj) _Py_XNewRef(_PyObject_CAST(obj)) #endif // bpo-39573 added Py_SET_REFCNT() to Python 3.9.0a4 #if PY_VERSION_HEX < 0x030900A4 && !defined(Py_SET_REFCNT) static inline void _Py_SET_REFCNT(PyObject *ob, Py_ssize_t refcnt) { ob->ob_refcnt = refcnt; } #define Py_SET_REFCNT(ob, refcnt) _Py_SET_REFCNT((PyObject*)(ob), refcnt) #endif // bpo-39573 added Py_SET_TYPE() to Python 3.9.0a4 #if PY_VERSION_HEX < 0x030900A4 && !defined(Py_SET_TYPE) static inline void _Py_SET_TYPE(PyObject *ob, PyTypeObject *type) { ob->ob_type = type; } #define Py_SET_TYPE(ob, type) _Py_SET_TYPE((PyObject*)(ob), type) #endif // bpo-39573 added Py_SET_SIZE() to Python 3.9.0a4 #if PY_VERSION_HEX < 0x030900A4 && !defined(Py_SET_SIZE) static inline void _Py_SET_SIZE(PyVarObject *ob, Py_ssize_t size) { ob->ob_size = size; } #define Py_SET_SIZE(ob, size) _Py_SET_SIZE((PyVarObject*)(ob), size) #endif // bpo-40421 added PyFrame_GetCode() to Python 3.9.0b1 #if PY_VERSION_HEX < 0x030900B1 static inline PyCodeObject* PyFrame_GetCode(PyFrameObject *frame) { PyCodeObject *code; assert(frame != NULL); code = frame->f_code; assert(code != NULL); Py_INCREF(code); return code; } #endif static inline PyCodeObject* _PyFrame_GetCodeBorrow(PyFrameObject *frame) { PyCodeObject *code = PyFrame_GetCode(frame); Py_DECREF(code); return code; // borrowed reference } // bpo-40421 added PyFrame_GetCode() to Python 3.9.0b1 #if PY_VERSION_HEX < 0x030900B1 static inline PyFrameObject* PyFrame_GetBack(PyFrameObject *frame) { PyFrameObject *back; assert(frame != NULL); back = frame->f_back; Py_XINCREF(back); return back; } #endif static inline PyFrameObject* _PyFrame_GetBackBorrow(PyFrameObject *frame) { PyFrameObject *back = PyFrame_GetBack(frame); Py_XDECREF(back); return back; // borrowed reference } // bpo-39947 added PyThreadState_GetInterpreter() to Python 3.9.0a5 #if PY_VERSION_HEX < 0x030900A5 static inline PyInterpreterState * PyThreadState_GetInterpreter(PyThreadState *tstate) { assert(tstate != NULL); return tstate->interp; } #endif // bpo-40429 added PyThreadState_GetFrame() to Python 3.9.0b1 #if PY_VERSION_HEX < 0x030900B1 static inline PyFrameObject* PyThreadState_GetFrame(PyThreadState *tstate) { PyFrameObject *frame; assert(tstate != NULL); frame = tstate->frame; Py_XINCREF(frame); return frame; } #endif static inline PyFrameObject* _PyThreadState_GetFrameBorrow(PyThreadState *tstate) { PyFrameObject *frame = PyThreadState_GetFrame(tstate); Py_XDECREF(frame); return frame; // borrowed reference } // bpo-39947 added PyInterpreterState_Get() to Python 3.9.0a5 #if PY_VERSION_HEX < 0x030900A5 static inline PyInterpreterState * PyInterpreterState_Get(void) { PyThreadState *tstate; PyInterpreterState *interp; tstate = PyThreadState_GET(); if (tstate == NULL) { Py_FatalError("GIL released (tstate is NULL)"); } interp = tstate->interp; if (interp == NULL) { Py_FatalError("no current interpreter"); } return interp; } #endif // bpo-39947 added PyInterpreterState_Get() to Python 3.9.0a6 #if 0x030700A1 <= PY_VERSION_HEX && PY_VERSION_HEX < 0x030900A6 static inline uint64_t PyThreadState_GetID(PyThreadState *tstate) { assert(tstate != NULL); return tstate->id; } #endif // bpo-37194 added PyObject_CallNoArgs() to Python 3.9.0a1 #if PY_VERSION_HEX < 0x030900A1 static inline PyObject* PyObject_CallNoArgs(PyObject *func) { return PyObject_CallFunctionObjArgs(func, NULL); } #endif // bpo-39245 made PyObject_CallOneArg() public (previously called // _PyObject_CallOneArg) in Python 3.9.0a4 #if PY_VERSION_HEX < 0x030900A4 static inline PyObject* PyObject_CallOneArg(PyObject *func, PyObject *arg) { return PyObject_CallFunctionObjArgs(func, arg, NULL); } #endif // bpo-40024 added PyModule_AddType() to Python 3.9.0a5 #if PY_VERSION_HEX < 0x030900A5 static inline int PyModule_AddType(PyObject *module, PyTypeObject *type) { const char *name, *dot; if (PyType_Ready(type) < 0) { return -1; } // inline _PyType_Name() name = type->tp_name; assert(name != NULL); dot = strrchr(name, '.'); if (dot != NULL) { name = dot + 1; } Py_INCREF(type); if (PyModule_AddObject(module, name, (PyObject *)type) < 0) { Py_DECREF(type); return -1; } return 0; } #endif // bpo-40241 added PyObject_GC_IsTracked() to Python 3.9.0a6. // bpo-4688 added _PyObject_GC_IS_TRACKED() to Python 2.7.0a2. #if PY_VERSION_HEX < 0x030900A6 static inline int PyObject_GC_IsTracked(PyObject* obj) { return (PyObject_IS_GC(obj) && _PyObject_GC_IS_TRACKED(obj)); } #endif // bpo-40241 added PyObject_GC_IsFinalized() to Python 3.9.0a6. // bpo-18112 added _PyGCHead_FINALIZED() to Python 3.4.0 final. #if PY_VERSION_HEX < 0x030900A6 && PY_VERSION_HEX >= 0x030400F0 static inline int PyObject_GC_IsFinalized(PyObject *obj) { return (PyObject_IS_GC(obj) && _PyGCHead_FINALIZED((PyGC_Head *)(obj)-1)); } #endif // bpo-39573 added Py_IS_TYPE() to Python 3.9.0a4 #if PY_VERSION_HEX < 0x030900A4 && !defined(Py_IS_TYPE) static inline int _Py_IS_TYPE(const PyObject *ob, const PyTypeObject *type) { return ob->ob_type == type; } #define Py_IS_TYPE(ob, type) _Py_IS_TYPE((const PyObject*)(ob), type) #endif #ifdef __cplusplus } #endif #endif // PYTHONCAPI_COMPAT