Victor Stinner | ed3b0bc | 2013-11-23 12:27:24 +0100 | [diff] [blame] | 1 | :mod:`tracemalloc` --- Trace memory allocations |
| 2 | =============================================== |
| 3 | |
| 4 | .. module:: tracemalloc |
| 5 | :synopsis: Trace memory allocations. |
| 6 | |
R David Murray | 6d5cb07 | 2013-12-20 14:48:50 -0500 | [diff] [blame] | 7 | .. versionadded:: 3.4 |
| 8 | |
Victor Stinner | ed3b0bc | 2013-11-23 12:27:24 +0100 | [diff] [blame] | 9 | The tracemalloc module is a debug tool to trace memory blocks allocated by |
| 10 | Python. It provides the following information: |
| 11 | |
| 12 | * Traceback where an object was allocated |
| 13 | * Statistics on allocated memory blocks per filename and per line number: |
| 14 | total size, number and average size of allocated memory blocks |
| 15 | * Compute the differences between two snapshots to detect memory leaks |
| 16 | |
| 17 | To trace most memory blocks allocated by Python, the module should be started |
| 18 | as early as possible by setting the :envvar:`PYTHONTRACEMALLOC` environment |
| 19 | variable to ``1``, or by using :option:`-X` ``tracemalloc`` command line |
| 20 | option. The :func:`tracemalloc.start` function can be called at runtime to |
| 21 | start tracing Python memory allocations. |
| 22 | |
| 23 | By default, a trace of an allocated memory block only stores the most recent |
| 24 | frame (1 frame). To store 25 frames at startup: set the |
| 25 | :envvar:`PYTHONTRACEMALLOC` environment variable to ``25``, or use the |
Victor Stinner | 3728d6c | 2013-11-23 12:37:20 +0100 | [diff] [blame] | 26 | :option:`-X` ``tracemalloc=25`` command line option. |
Victor Stinner | ed3b0bc | 2013-11-23 12:27:24 +0100 | [diff] [blame] | 27 | |
Victor Stinner | ed3b0bc | 2013-11-23 12:27:24 +0100 | [diff] [blame] | 28 | |
| 29 | Examples |
| 30 | ======== |
| 31 | |
| 32 | Display the top 10 |
| 33 | ------------------ |
| 34 | |
| 35 | Display the 10 files allocating the most memory:: |
| 36 | |
| 37 | import tracemalloc |
| 38 | |
| 39 | tracemalloc.start() |
| 40 | |
| 41 | # ... run your application ... |
| 42 | |
| 43 | snapshot = tracemalloc.take_snapshot() |
| 44 | top_stats = snapshot.statistics('lineno') |
| 45 | |
| 46 | print("[ Top 10 ]") |
| 47 | for stat in top_stats[:10]: |
| 48 | print(stat) |
| 49 | |
| 50 | |
| 51 | Example of output of the Python test suite:: |
| 52 | |
| 53 | [ Top 10 ] |
| 54 | <frozen importlib._bootstrap>:716: size=4855 KiB, count=39328, average=126 B |
| 55 | <frozen importlib._bootstrap>:284: size=521 KiB, count=3199, average=167 B |
| 56 | /usr/lib/python3.4/collections/__init__.py:368: size=244 KiB, count=2315, average=108 B |
| 57 | /usr/lib/python3.4/unittest/case.py:381: size=185 KiB, count=779, average=243 B |
| 58 | /usr/lib/python3.4/unittest/case.py:402: size=154 KiB, count=378, average=416 B |
| 59 | /usr/lib/python3.4/abc.py:133: size=88.7 KiB, count=347, average=262 B |
| 60 | <frozen importlib._bootstrap>:1446: size=70.4 KiB, count=911, average=79 B |
| 61 | <frozen importlib._bootstrap>:1454: size=52.0 KiB, count=25, average=2131 B |
| 62 | <string>:5: size=49.7 KiB, count=148, average=344 B |
| 63 | /usr/lib/python3.4/sysconfig.py:411: size=48.0 KiB, count=1, average=48.0 KiB |
| 64 | |
| 65 | We can see that Python loaded ``4.8 MiB`` data (bytecode and constants) from |
| 66 | modules and that the :mod:`collections` module allocated ``244 KiB`` to build |
| 67 | :class:`~collections.namedtuple` types. |
| 68 | |
| 69 | See :meth:`Snapshot.statistics` for more options. |
| 70 | |
| 71 | |
| 72 | Compute differences |
| 73 | ------------------- |
| 74 | |
| 75 | Take two snapshots and display the differences:: |
| 76 | |
| 77 | import tracemalloc |
| 78 | tracemalloc.start() |
| 79 | # ... start your application ... |
| 80 | |
| 81 | snapshot1 = tracemalloc.take_snapshot() |
| 82 | # ... call the function leaking memory ... |
| 83 | snapshot2 = tracemalloc.take_snapshot() |
| 84 | |
| 85 | top_stats = snapshot2.compare_to(snapshot1, 'lineno') |
| 86 | |
| 87 | print("[ Top 10 differences ]") |
| 88 | for stat in top_stats[:10]: |
| 89 | print(stat) |
| 90 | |
| 91 | Example of output before/after running some tests of the Python test suite:: |
| 92 | |
| 93 | [ Top 10 differences ] |
| 94 | <frozen importlib._bootstrap>:716: size=8173 KiB (+4428 KiB), count=71332 (+39369), average=117 B |
| 95 | /usr/lib/python3.4/linecache.py:127: size=940 KiB (+940 KiB), count=8106 (+8106), average=119 B |
| 96 | /usr/lib/python3.4/unittest/case.py:571: size=298 KiB (+298 KiB), count=589 (+589), average=519 B |
| 97 | <frozen importlib._bootstrap>:284: size=1005 KiB (+166 KiB), count=7423 (+1526), average=139 B |
| 98 | /usr/lib/python3.4/mimetypes.py:217: size=112 KiB (+112 KiB), count=1334 (+1334), average=86 B |
| 99 | /usr/lib/python3.4/http/server.py:848: size=96.0 KiB (+96.0 KiB), count=1 (+1), average=96.0 KiB |
| 100 | /usr/lib/python3.4/inspect.py:1465: size=83.5 KiB (+83.5 KiB), count=109 (+109), average=784 B |
| 101 | /usr/lib/python3.4/unittest/mock.py:491: size=77.7 KiB (+77.7 KiB), count=143 (+143), average=557 B |
| 102 | /usr/lib/python3.4/urllib/parse.py:476: size=71.8 KiB (+71.8 KiB), count=969 (+969), average=76 B |
| 103 | /usr/lib/python3.4/contextlib.py:38: size=67.2 KiB (+67.2 KiB), count=126 (+126), average=546 B |
| 104 | |
Victor Stinner | 00773df | 2013-11-26 00:40:10 +0100 | [diff] [blame] | 105 | We can see that Python has loaded ``8.2 MiB`` of module data (bytecode and |
| 106 | constants), and that this is ``4.4 MiB`` more than had been loaded before the |
| 107 | tests, when the previous snapshot was taken. Similarly, the :mod:`linecache` |
| 108 | module has cached ``940 KiB`` of Python source code to format tracebacks, all |
| 109 | of it since the previous snapshot. |
Victor Stinner | ed3b0bc | 2013-11-23 12:27:24 +0100 | [diff] [blame] | 110 | |
| 111 | If the system has little free memory, snapshots can be written on disk using |
| 112 | the :meth:`Snapshot.dump` method to analyze the snapshot offline. Then use the |
| 113 | :meth:`Snapshot.load` method reload the snapshot. |
| 114 | |
| 115 | |
| 116 | Get the traceback of a memory block |
| 117 | ----------------------------------- |
| 118 | |
| 119 | Code to display the traceback of the biggest memory block:: |
| 120 | |
| 121 | import linecache |
| 122 | import tracemalloc |
| 123 | |
Victor Stinner | 3728d6c | 2013-11-23 12:37:20 +0100 | [diff] [blame] | 124 | # Store 25 frames |
| 125 | tracemalloc.start(25) |
Victor Stinner | ed3b0bc | 2013-11-23 12:27:24 +0100 | [diff] [blame] | 126 | |
| 127 | # ... run your application ... |
| 128 | |
| 129 | snapshot = tracemalloc.take_snapshot() |
| 130 | top_stats = snapshot.statistics('traceback') |
| 131 | |
| 132 | # pick the biggest memory block |
| 133 | stat = top_stats[0] |
| 134 | print("%s memory blocks: %.1f KiB" % (stat.count, stat.size / 1024)) |
| 135 | for frame in stat.traceback: |
| 136 | print(' File "%s", line %s' % (frame.filename, frame.lineno)) |
| 137 | line = linecache.getline(frame.filename, frame.lineno) |
| 138 | line = line.strip() |
| 139 | if line: |
| 140 | print(' ' + line) |
| 141 | |
| 142 | Example of output of the Python test suite (traceback limited to 25 frames):: |
| 143 | |
| 144 | 903 memory blocks: 870.1 KiB |
| 145 | File "<frozen importlib._bootstrap>", line 716 |
| 146 | File "<frozen importlib._bootstrap>", line 1036 |
| 147 | File "<frozen importlib._bootstrap>", line 934 |
| 148 | File "<frozen importlib._bootstrap>", line 1068 |
| 149 | File "<frozen importlib._bootstrap>", line 619 |
| 150 | File "<frozen importlib._bootstrap>", line 1581 |
| 151 | File "<frozen importlib._bootstrap>", line 1614 |
| 152 | File "/usr/lib/python3.4/doctest.py", line 101 |
| 153 | import pdb |
| 154 | File "<frozen importlib._bootstrap>", line 284 |
| 155 | File "<frozen importlib._bootstrap>", line 938 |
| 156 | File "<frozen importlib._bootstrap>", line 1068 |
| 157 | File "<frozen importlib._bootstrap>", line 619 |
| 158 | File "<frozen importlib._bootstrap>", line 1581 |
| 159 | File "<frozen importlib._bootstrap>", line 1614 |
| 160 | File "/usr/lib/python3.4/test/support/__init__.py", line 1728 |
| 161 | import doctest |
| 162 | File "/usr/lib/python3.4/test/test_pickletools.py", line 21 |
| 163 | support.run_doctest(pickletools) |
| 164 | File "/usr/lib/python3.4/test/regrtest.py", line 1276 |
| 165 | test_runner() |
| 166 | File "/usr/lib/python3.4/test/regrtest.py", line 976 |
| 167 | display_failure=not verbose) |
| 168 | File "/usr/lib/python3.4/test/regrtest.py", line 761 |
| 169 | match_tests=ns.match_tests) |
| 170 | File "/usr/lib/python3.4/test/regrtest.py", line 1563 |
| 171 | main() |
| 172 | File "/usr/lib/python3.4/test/__main__.py", line 3 |
| 173 | regrtest.main_in_temp_cwd() |
| 174 | File "/usr/lib/python3.4/runpy.py", line 73 |
| 175 | exec(code, run_globals) |
| 176 | File "/usr/lib/python3.4/runpy.py", line 160 |
| 177 | "__main__", fname, loader, pkg_name) |
| 178 | |
Victor Stinner | 00773df | 2013-11-26 00:40:10 +0100 | [diff] [blame] | 179 | We can see that the most memory was allocated in the :mod:`importlib` module to |
Victor Stinner | ed3b0bc | 2013-11-23 12:27:24 +0100 | [diff] [blame] | 180 | load data (bytecode and constants) from modules: ``870 KiB``. The traceback is |
Victor Stinner | 00773df | 2013-11-26 00:40:10 +0100 | [diff] [blame] | 181 | where the :mod:`importlib` loaded data most recently: on the ``import pdb`` |
| 182 | line of the :mod:`doctest` module. The traceback may change if a new module is |
| 183 | loaded. |
Victor Stinner | ed3b0bc | 2013-11-23 12:27:24 +0100 | [diff] [blame] | 184 | |
| 185 | |
| 186 | Pretty top |
| 187 | ---------- |
| 188 | |
| 189 | Code to display the 10 lines allocating the most memory with a pretty output, |
| 190 | ignoring ``<frozen importlib._bootstrap>`` and ``<unknown>`` files:: |
| 191 | |
| 192 | import os |
| 193 | import tracemalloc |
| 194 | |
| 195 | def display_top(snapshot, group_by='lineno', limit=10): |
| 196 | snapshot = snapshot.filter_traces(( |
| 197 | tracemalloc.Filter(False, "<frozen importlib._bootstrap>"), |
| 198 | tracemalloc.Filter(False, "<unknown>"), |
| 199 | )) |
| 200 | top_stats = snapshot.statistics(group_by) |
| 201 | |
| 202 | print("Top %s lines" % limit) |
| 203 | for index, stat in enumerate(top_stats[:limit], 1): |
| 204 | frame = stat.traceback[0] |
| 205 | # replace "/path/to/module/file.py" with "module/file.py" |
| 206 | filename = os.sep.join(frame.filename.split(os.sep)[-2:]) |
| 207 | print("#%s: %s:%s: %.1f KiB" |
| 208 | % (index, filename, frame.lineno, |
| 209 | stat.size / 1024)) |
| 210 | |
| 211 | other = top_stats[limit:] |
| 212 | if other: |
| 213 | size = sum(stat.size for stat in other) |
| 214 | print("%s other: %.1f KiB" % (len(other), size / 1024)) |
| 215 | total = sum(stat.size for stat in top_stats) |
| 216 | print("Total allocated size: %.1f KiB" % (total / 1024)) |
| 217 | |
| 218 | tracemalloc.start() |
| 219 | |
| 220 | # ... run your application ... |
| 221 | |
| 222 | snapshot = tracemalloc.take_snapshot() |
| 223 | display_top(snapshot, 10) |
| 224 | |
| 225 | Example of output of the Python test suite:: |
| 226 | |
| 227 | 2013-11-08 14:16:58.149320: Top 10 lines |
| 228 | #1: collections/__init__.py:368: 291.9 KiB |
| 229 | #2: Lib/doctest.py:1291: 200.2 KiB |
| 230 | #3: unittest/case.py:571: 160.3 KiB |
| 231 | #4: Lib/abc.py:133: 99.8 KiB |
| 232 | #5: urllib/parse.py:476: 71.8 KiB |
| 233 | #6: <string>:5: 62.7 KiB |
| 234 | #7: Lib/base64.py:140: 59.8 KiB |
| 235 | #8: Lib/_weakrefset.py:37: 51.8 KiB |
| 236 | #9: collections/__init__.py:362: 50.6 KiB |
| 237 | #10: test/test_site.py:56: 48.0 KiB |
| 238 | 7496 other: 4161.9 KiB |
| 239 | Total allocated size: 5258.8 KiB |
| 240 | |
| 241 | See :meth:`Snapshot.statistics` for more options. |
| 242 | |
| 243 | |
| 244 | API |
| 245 | === |
| 246 | |
| 247 | Functions |
| 248 | --------- |
| 249 | |
| 250 | .. function:: clear_traces() |
| 251 | |
| 252 | Clear traces of memory blocks allocated by Python. |
| 253 | |
| 254 | See also :func:`stop`. |
| 255 | |
| 256 | |
| 257 | .. function:: get_object_traceback(obj) |
| 258 | |
| 259 | Get the traceback where the Python object *obj* was allocated. |
| 260 | Return a :class:`Traceback` instance, or ``None`` if the :mod:`tracemalloc` |
| 261 | module is not tracing memory allocations or did not trace the allocation of |
| 262 | the object. |
| 263 | |
| 264 | See also :func:`gc.get_referrers` and :func:`sys.getsizeof` functions. |
| 265 | |
| 266 | |
| 267 | .. function:: get_traceback_limit() |
| 268 | |
| 269 | Get the maximum number of frames stored in the traceback of a trace. |
| 270 | |
Victor Stinner | 3728d6c | 2013-11-23 12:37:20 +0100 | [diff] [blame] | 271 | The :mod:`tracemalloc` module must be tracing memory allocations to |
| 272 | get the limit, otherwise an exception is raised. |
Victor Stinner | ed3b0bc | 2013-11-23 12:27:24 +0100 | [diff] [blame] | 273 | |
Victor Stinner | 3728d6c | 2013-11-23 12:37:20 +0100 | [diff] [blame] | 274 | The limit is set by the :func:`start` function. |
Victor Stinner | ed3b0bc | 2013-11-23 12:27:24 +0100 | [diff] [blame] | 275 | |
| 276 | |
| 277 | .. function:: get_traced_memory() |
| 278 | |
Victor Stinner | 3c0481d | 2013-11-27 21:39:49 +0100 | [diff] [blame] | 279 | Get the current size and peak size of memory blocks traced by the |
| 280 | :mod:`tracemalloc` module as a tuple: ``(current: int, peak: int)``. |
Victor Stinner | ed3b0bc | 2013-11-23 12:27:24 +0100 | [diff] [blame] | 281 | |
| 282 | |
| 283 | .. function:: get_tracemalloc_memory() |
| 284 | |
| 285 | Get the memory usage in bytes of the :mod:`tracemalloc` module used to store |
| 286 | traces of memory blocks. |
| 287 | Return an :class:`int`. |
| 288 | |
| 289 | |
| 290 | .. function:: is_tracing() |
| 291 | |
| 292 | ``True`` if the :mod:`tracemalloc` module is tracing Python memory |
| 293 | allocations, ``False`` otherwise. |
| 294 | |
| 295 | See also :func:`start` and :func:`stop` functions. |
| 296 | |
| 297 | |
Victor Stinner | 3728d6c | 2013-11-23 12:37:20 +0100 | [diff] [blame] | 298 | .. function:: start(nframe: int=1) |
Victor Stinner | ed3b0bc | 2013-11-23 12:27:24 +0100 | [diff] [blame] | 299 | |
Victor Stinner | 3728d6c | 2013-11-23 12:37:20 +0100 | [diff] [blame] | 300 | Start tracing Python memory allocations: install hooks on Python memory |
| 301 | allocators. Collected tracebacks of traces will be limited to *nframe* |
| 302 | frames. By default, a trace of a memory block only stores the most recent |
| 303 | frame: the limit is ``1``. *nframe* must be greater or equal to ``1``. |
Victor Stinner | ed3b0bc | 2013-11-23 12:27:24 +0100 | [diff] [blame] | 304 | |
| 305 | Storing more than ``1`` frame is only useful to compute statistics grouped |
| 306 | by ``'traceback'`` or to compute cumulative statistics: see the |
| 307 | :meth:`Snapshot.compare_to` and :meth:`Snapshot.statistics` methods. |
| 308 | |
| 309 | Storing more frames increases the memory and CPU overhead of the |
| 310 | :mod:`tracemalloc` module. Use the :func:`get_tracemalloc_memory` function |
| 311 | to measure how much memory is used by the :mod:`tracemalloc` module. |
| 312 | |
| 313 | The :envvar:`PYTHONTRACEMALLOC` environment variable |
| 314 | (``PYTHONTRACEMALLOC=NFRAME``) and the :option:`-X` ``tracemalloc=NFRAME`` |
Victor Stinner | 3728d6c | 2013-11-23 12:37:20 +0100 | [diff] [blame] | 315 | command line option can be used to start tracing at startup. |
Victor Stinner | ed3b0bc | 2013-11-23 12:27:24 +0100 | [diff] [blame] | 316 | |
Victor Stinner | 3728d6c | 2013-11-23 12:37:20 +0100 | [diff] [blame] | 317 | See also :func:`stop`, :func:`is_tracing` and :func:`get_traceback_limit` |
| 318 | functions. |
Victor Stinner | ed3b0bc | 2013-11-23 12:27:24 +0100 | [diff] [blame] | 319 | |
| 320 | |
| 321 | .. function:: stop() |
| 322 | |
| 323 | Stop tracing Python memory allocations: uninstall hooks on Python memory |
Victor Stinner | 00773df | 2013-11-26 00:40:10 +0100 | [diff] [blame] | 324 | allocators. Also clears all previously collected traces of memory blocks |
| 325 | allocated by Python. |
Victor Stinner | ed3b0bc | 2013-11-23 12:27:24 +0100 | [diff] [blame] | 326 | |
| 327 | Call :func:`take_snapshot` function to take a snapshot of traces before |
| 328 | clearing them. |
| 329 | |
Victor Stinner | 00773df | 2013-11-26 00:40:10 +0100 | [diff] [blame] | 330 | See also :func:`start`, :func:`is_tracing` and :func:`clear_traces` |
| 331 | functions. |
Victor Stinner | ed3b0bc | 2013-11-23 12:27:24 +0100 | [diff] [blame] | 332 | |
| 333 | |
| 334 | .. function:: take_snapshot() |
| 335 | |
| 336 | Take a snapshot of traces of memory blocks allocated by Python. Return a new |
| 337 | :class:`Snapshot` instance. |
| 338 | |
| 339 | The snapshot does not include memory blocks allocated before the |
| 340 | :mod:`tracemalloc` module started to trace memory allocations. |
| 341 | |
| 342 | Tracebacks of traces are limited to :func:`get_traceback_limit` frames. Use |
Victor Stinner | 3728d6c | 2013-11-23 12:37:20 +0100 | [diff] [blame] | 343 | the *nframe* parameter of the :func:`start` function to store more frames. |
Victor Stinner | ed3b0bc | 2013-11-23 12:27:24 +0100 | [diff] [blame] | 344 | |
| 345 | The :mod:`tracemalloc` module must be tracing memory allocations to take a |
| 346 | snapshot, see the the :func:`start` function. |
| 347 | |
| 348 | See also the :func:`get_object_traceback` function. |
| 349 | |
| 350 | |
| 351 | Filter |
| 352 | ------ |
| 353 | |
| 354 | .. class:: Filter(inclusive: bool, filename_pattern: str, lineno: int=None, all_frames: bool=False) |
| 355 | |
| 356 | Filter on traces of memory blocks. |
| 357 | |
| 358 | See the :func:`fnmatch.fnmatch` function for the syntax of |
| 359 | *filename_pattern*. The ``'.pyc'`` and ``'.pyo'`` file extensions are |
| 360 | replaced with ``'.py'``. |
| 361 | |
| 362 | Examples: |
| 363 | |
| 364 | * ``Filter(True, subprocess.__file__)`` only includes traces of the |
| 365 | :mod:`subprocess` module |
| 366 | * ``Filter(False, tracemalloc.__file__)`` excludes traces of the |
| 367 | :mod:`tracemalloc` module |
| 368 | * ``Filter(False, "<unknown>")`` excludes empty tracebacks |
| 369 | |
| 370 | .. attribute:: inclusive |
| 371 | |
| 372 | If *inclusive* is ``True`` (include), only trace memory blocks allocated |
| 373 | in a file with a name matching :attr:`filename_pattern` at line number |
| 374 | :attr:`lineno`. |
| 375 | |
| 376 | If *inclusive* is ``False`` (exclude), ignore memory blocks allocated in |
| 377 | a file with a name matching :attr:`filename_pattern` at line number |
| 378 | :attr:`lineno`. |
| 379 | |
| 380 | .. attribute:: lineno |
| 381 | |
| 382 | Line number (``int``) of the filter. If *lineno* is ``None``, the filter |
| 383 | matches any line number. |
| 384 | |
| 385 | .. attribute:: filename_pattern |
| 386 | |
| 387 | Filename pattern of the filter (``str``). |
| 388 | |
| 389 | .. attribute:: all_frames |
| 390 | |
| 391 | If *all_frames* is ``True``, all frames of the traceback are checked. If |
| 392 | *all_frames* is ``False``, only the most recent frame is checked. |
| 393 | |
Victor Stinner | 5362abf | 2013-11-27 23:39:55 +0100 | [diff] [blame] | 394 | This attribute has no effect if the traceback limit is ``1``. See the |
| 395 | :func:`get_traceback_limit` function and :attr:`Snapshot.traceback_limit` |
| 396 | attribute. |
Victor Stinner | ed3b0bc | 2013-11-23 12:27:24 +0100 | [diff] [blame] | 397 | |
| 398 | |
| 399 | Frame |
| 400 | ----- |
| 401 | |
| 402 | .. class:: Frame |
| 403 | |
| 404 | Frame of a traceback. |
| 405 | |
| 406 | The :class:`Traceback` class is a sequence of :class:`Frame` instances. |
| 407 | |
| 408 | .. attribute:: filename |
| 409 | |
| 410 | Filename (``str``). |
| 411 | |
| 412 | .. attribute:: lineno |
| 413 | |
| 414 | Line number (``int``). |
| 415 | |
| 416 | |
| 417 | Snapshot |
| 418 | -------- |
| 419 | |
| 420 | .. class:: Snapshot |
| 421 | |
| 422 | Snapshot of traces of memory blocks allocated by Python. |
| 423 | |
| 424 | The :func:`take_snapshot` function creates a snapshot instance. |
| 425 | |
| 426 | .. method:: compare_to(old_snapshot: Snapshot, group_by: str, cumulative: bool=False) |
| 427 | |
| 428 | Compute the differences with an old snapshot. Get statistics as a sorted |
| 429 | list of :class:`StatisticDiff` instances grouped by *group_by*. |
| 430 | |
| 431 | See the :meth:`statistics` method for *group_by* and *cumulative* |
| 432 | parameters. |
| 433 | |
| 434 | The result is sorted from the biggest to the smallest by: absolute value |
| 435 | of :attr:`StatisticDiff.size_diff`, :attr:`StatisticDiff.size`, absolute |
| 436 | value of :attr:`StatisticDiff.count_diff`, :attr:`Statistic.count` and |
| 437 | then by :attr:`StatisticDiff.traceback`. |
| 438 | |
| 439 | |
| 440 | .. method:: dump(filename) |
| 441 | |
| 442 | Write the snapshot into a file. |
| 443 | |
| 444 | Use :meth:`load` to reload the snapshot. |
| 445 | |
| 446 | |
| 447 | .. method:: filter_traces(filters) |
| 448 | |
| 449 | Create a new :class:`Snapshot` instance with a filtered :attr:`traces` |
| 450 | sequence, *filters* is a list of :class:`Filter` instances. If *filters* |
| 451 | is an empty list, return a new :class:`Snapshot` instance with a copy of |
| 452 | the traces. |
| 453 | |
| 454 | All inclusive filters are applied at once, a trace is ignored if no |
| 455 | inclusive filters match it. A trace is ignored if at least one exclusive |
| 456 | filter matchs it. |
| 457 | |
| 458 | |
| 459 | .. classmethod:: load(filename) |
| 460 | |
| 461 | Load a snapshot from a file. |
| 462 | |
| 463 | See also :meth:`dump`. |
| 464 | |
| 465 | |
| 466 | .. method:: statistics(group_by: str, cumulative: bool=False) |
| 467 | |
| 468 | Get statistics as a sorted list of :class:`Statistic` instances grouped |
| 469 | by *group_by*: |
| 470 | |
| 471 | ===================== ======================== |
| 472 | group_by description |
| 473 | ===================== ======================== |
| 474 | ``'filename'`` filename |
| 475 | ``'lineno'`` filename and line number |
| 476 | ``'traceback'`` traceback |
| 477 | ===================== ======================== |
| 478 | |
| 479 | If *cumulative* is ``True``, cumulate size and count of memory blocks of |
| 480 | all frames of the traceback of a trace, not only the most recent frame. |
| 481 | The cumulative mode can only be used with *group_by* equals to |
Victor Stinner | 8e3708d | 2013-11-26 00:45:47 +0100 | [diff] [blame] | 482 | ``'filename'`` and ``'lineno'``. |
Victor Stinner | ed3b0bc | 2013-11-23 12:27:24 +0100 | [diff] [blame] | 483 | |
| 484 | The result is sorted from the biggest to the smallest by: |
| 485 | :attr:`Statistic.size`, :attr:`Statistic.count` and then by |
| 486 | :attr:`Statistic.traceback`. |
| 487 | |
| 488 | |
| 489 | .. attribute:: traceback_limit |
| 490 | |
| 491 | Maximum number of frames stored in the traceback of :attr:`traces`: |
| 492 | result of the :func:`get_traceback_limit` when the snapshot was taken. |
| 493 | |
| 494 | .. attribute:: traces |
| 495 | |
| 496 | Traces of all memory blocks allocated by Python: sequence of |
| 497 | :class:`Trace` instances. |
| 498 | |
| 499 | The sequence has an undefined order. Use the :meth:`Snapshot.statistics` |
| 500 | method to get a sorted list of statistics. |
| 501 | |
| 502 | |
| 503 | Statistic |
| 504 | --------- |
| 505 | |
| 506 | .. class:: Statistic |
| 507 | |
| 508 | Statistic on memory allocations. |
| 509 | |
| 510 | :func:`Snapshot.statistics` returns a list of :class:`Statistic` instances. |
| 511 | |
| 512 | See also the :class:`StatisticDiff` class. |
| 513 | |
| 514 | .. attribute:: count |
| 515 | |
| 516 | Number of memory blocks (``int``). |
| 517 | |
| 518 | .. attribute:: size |
| 519 | |
| 520 | Total size of memory blocks in bytes (``int``). |
| 521 | |
| 522 | .. attribute:: traceback |
| 523 | |
| 524 | Traceback where the memory block was allocated, :class:`Traceback` |
| 525 | instance. |
| 526 | |
| 527 | |
| 528 | StatisticDiff |
| 529 | ------------- |
| 530 | |
| 531 | .. class:: StatisticDiff |
| 532 | |
| 533 | Statistic difference on memory allocations between an old and a new |
| 534 | :class:`Snapshot` instance. |
| 535 | |
| 536 | :func:`Snapshot.compare_to` returns a list of :class:`StatisticDiff` |
| 537 | instances. See also the :class:`Statistic` class. |
| 538 | |
| 539 | .. attribute:: count |
| 540 | |
| 541 | Number of memory blocks in the new snapshot (``int``): ``0`` if |
| 542 | the memory blocks have been released in the new snapshot. |
| 543 | |
| 544 | .. attribute:: count_diff |
| 545 | |
| 546 | Difference of number of memory blocks between the old and the new |
| 547 | snapshots (``int``): ``0`` if the memory blocks have been allocated in |
| 548 | the new snapshot. |
| 549 | |
| 550 | .. attribute:: size |
| 551 | |
| 552 | Total size of memory blocks in bytes in the new snapshot (``int``): |
| 553 | ``0`` if the memory blocks have been released in the new snapshot. |
| 554 | |
| 555 | .. attribute:: size_diff |
| 556 | |
| 557 | Difference of total size of memory blocks in bytes between the old and |
| 558 | the new snapshots (``int``): ``0`` if the memory blocks have been |
| 559 | allocated in the new snapshot. |
| 560 | |
| 561 | .. attribute:: traceback |
| 562 | |
| 563 | Traceback where the memory blocks were allocated, :class:`Traceback` |
| 564 | instance. |
| 565 | |
| 566 | |
| 567 | Trace |
| 568 | ----- |
| 569 | |
| 570 | .. class:: Trace |
| 571 | |
| 572 | Trace of a memory block. |
| 573 | |
| 574 | The :attr:`Snapshot.traces` attribute is a sequence of :class:`Trace` |
| 575 | instances. |
| 576 | |
| 577 | .. attribute:: size |
| 578 | |
| 579 | Size of the memory block in bytes (``int``). |
| 580 | |
| 581 | .. attribute:: traceback |
| 582 | |
| 583 | Traceback where the memory block was allocated, :class:`Traceback` |
| 584 | instance. |
| 585 | |
| 586 | |
| 587 | Traceback |
| 588 | --------- |
| 589 | |
| 590 | .. class:: Traceback |
| 591 | |
| 592 | Sequence of :class:`Frame` instances sorted from the most recent frame to |
| 593 | the oldest frame. |
| 594 | |
| 595 | A traceback contains at least ``1`` frame. If the ``tracemalloc`` module |
| 596 | failed to get a frame, the filename ``"<unknown>"`` at line number ``0`` is |
| 597 | used. |
| 598 | |
| 599 | When a snapshot is taken, tracebacks of traces are limited to |
| 600 | :func:`get_traceback_limit` frames. See the :func:`take_snapshot` function. |
| 601 | |
| 602 | The :attr:`Trace.traceback` attribute is an instance of :class:`Traceback` |
| 603 | instance. |
| 604 | |
| 605 | |