mirror of
https://github.com/python/cpython.git
synced 2025-10-27 08:46:53 +00:00
765 lines
25 KiB
ReStructuredText
765 lines
25 KiB
ReStructuredText
:mod:`tracemalloc` --- Trace memory allocations
|
|
===============================================
|
|
|
|
.. module:: tracemalloc
|
|
:synopsis: Trace memory allocations.
|
|
|
|
.. versionadded:: 3.4
|
|
|
|
**Source code:** :source:`Lib/tracemalloc.py`
|
|
|
|
--------------
|
|
|
|
The tracemalloc module is a debug tool to trace memory blocks allocated by
|
|
Python. It provides the following information:
|
|
|
|
* Traceback where an object was allocated
|
|
* Statistics on allocated memory blocks per filename and per line number:
|
|
total size, number and average size of allocated memory blocks
|
|
* Compute the differences between two snapshots to detect memory leaks
|
|
|
|
To trace most memory blocks allocated by Python, the module should be started
|
|
as early as possible by setting the :envvar:`PYTHONTRACEMALLOC` environment
|
|
variable to ``1``, or by using :option:`-X` ``tracemalloc`` command line
|
|
option. The :func:`tracemalloc.start` function can be called at runtime to
|
|
start tracing Python memory allocations.
|
|
|
|
By default, a trace of an allocated memory block only stores the most recent
|
|
frame (1 frame). To store 25 frames at startup: set the
|
|
:envvar:`PYTHONTRACEMALLOC` environment variable to ``25``, or use the
|
|
:option:`-X` ``tracemalloc=25`` command line option.
|
|
|
|
|
|
Examples
|
|
--------
|
|
|
|
Display the top 10
|
|
^^^^^^^^^^^^^^^^^^
|
|
|
|
Display the 10 files allocating the most memory::
|
|
|
|
import tracemalloc
|
|
|
|
tracemalloc.start()
|
|
|
|
# ... run your application ...
|
|
|
|
snapshot = tracemalloc.take_snapshot()
|
|
top_stats = snapshot.statistics('lineno')
|
|
|
|
print("[ Top 10 ]")
|
|
for stat in top_stats[:10]:
|
|
print(stat)
|
|
|
|
|
|
Example of output of the Python test suite::
|
|
|
|
[ Top 10 ]
|
|
<frozen importlib._bootstrap>:716: size=4855 KiB, count=39328, average=126 B
|
|
<frozen importlib._bootstrap>:284: size=521 KiB, count=3199, average=167 B
|
|
/usr/lib/python3.4/collections/__init__.py:368: size=244 KiB, count=2315, average=108 B
|
|
/usr/lib/python3.4/unittest/case.py:381: size=185 KiB, count=779, average=243 B
|
|
/usr/lib/python3.4/unittest/case.py:402: size=154 KiB, count=378, average=416 B
|
|
/usr/lib/python3.4/abc.py:133: size=88.7 KiB, count=347, average=262 B
|
|
<frozen importlib._bootstrap>:1446: size=70.4 KiB, count=911, average=79 B
|
|
<frozen importlib._bootstrap>:1454: size=52.0 KiB, count=25, average=2131 B
|
|
<string>:5: size=49.7 KiB, count=148, average=344 B
|
|
/usr/lib/python3.4/sysconfig.py:411: size=48.0 KiB, count=1, average=48.0 KiB
|
|
|
|
We can see that Python loaded ``4855 KiB`` data (bytecode and constants) from
|
|
modules and that the :mod:`collections` module allocated ``244 KiB`` to build
|
|
:class:`~collections.namedtuple` types.
|
|
|
|
See :meth:`Snapshot.statistics` for more options.
|
|
|
|
|
|
Compute differences
|
|
^^^^^^^^^^^^^^^^^^^
|
|
|
|
Take two snapshots and display the differences::
|
|
|
|
import tracemalloc
|
|
tracemalloc.start()
|
|
# ... start your application ...
|
|
|
|
snapshot1 = tracemalloc.take_snapshot()
|
|
# ... call the function leaking memory ...
|
|
snapshot2 = tracemalloc.take_snapshot()
|
|
|
|
top_stats = snapshot2.compare_to(snapshot1, 'lineno')
|
|
|
|
print("[ Top 10 differences ]")
|
|
for stat in top_stats[:10]:
|
|
print(stat)
|
|
|
|
Example of output before/after running some tests of the Python test suite::
|
|
|
|
[ Top 10 differences ]
|
|
<frozen importlib._bootstrap>:716: size=8173 KiB (+4428 KiB), count=71332 (+39369), average=117 B
|
|
/usr/lib/python3.4/linecache.py:127: size=940 KiB (+940 KiB), count=8106 (+8106), average=119 B
|
|
/usr/lib/python3.4/unittest/case.py:571: size=298 KiB (+298 KiB), count=589 (+589), average=519 B
|
|
<frozen importlib._bootstrap>:284: size=1005 KiB (+166 KiB), count=7423 (+1526), average=139 B
|
|
/usr/lib/python3.4/mimetypes.py:217: size=112 KiB (+112 KiB), count=1334 (+1334), average=86 B
|
|
/usr/lib/python3.4/http/server.py:848: size=96.0 KiB (+96.0 KiB), count=1 (+1), average=96.0 KiB
|
|
/usr/lib/python3.4/inspect.py:1465: size=83.5 KiB (+83.5 KiB), count=109 (+109), average=784 B
|
|
/usr/lib/python3.4/unittest/mock.py:491: size=77.7 KiB (+77.7 KiB), count=143 (+143), average=557 B
|
|
/usr/lib/python3.4/urllib/parse.py:476: size=71.8 KiB (+71.8 KiB), count=969 (+969), average=76 B
|
|
/usr/lib/python3.4/contextlib.py:38: size=67.2 KiB (+67.2 KiB), count=126 (+126), average=546 B
|
|
|
|
We can see that Python has loaded ``8173 KiB`` of module data (bytecode and
|
|
constants), and that this is ``4428 KiB`` more than had been loaded before the
|
|
tests, when the previous snapshot was taken. Similarly, the :mod:`linecache`
|
|
module has cached ``940 KiB`` of Python source code to format tracebacks, all
|
|
of it since the previous snapshot.
|
|
|
|
If the system has little free memory, snapshots can be written on disk using
|
|
the :meth:`Snapshot.dump` method to analyze the snapshot offline. Then use the
|
|
:meth:`Snapshot.load` method reload the snapshot.
|
|
|
|
|
|
Get the traceback of a memory block
|
|
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
|
|
|
|
Code to display the traceback of the biggest memory block::
|
|
|
|
import tracemalloc
|
|
|
|
# Store 25 frames
|
|
tracemalloc.start(25)
|
|
|
|
# ... run your application ...
|
|
|
|
snapshot = tracemalloc.take_snapshot()
|
|
top_stats = snapshot.statistics('traceback')
|
|
|
|
# pick the biggest memory block
|
|
stat = top_stats[0]
|
|
print("%s memory blocks: %.1f KiB" % (stat.count, stat.size / 1024))
|
|
for line in stat.traceback.format():
|
|
print(line)
|
|
|
|
Example of output of the Python test suite (traceback limited to 25 frames)::
|
|
|
|
903 memory blocks: 870.1 KiB
|
|
File "<frozen importlib._bootstrap>", line 716
|
|
File "<frozen importlib._bootstrap>", line 1036
|
|
File "<frozen importlib._bootstrap>", line 934
|
|
File "<frozen importlib._bootstrap>", line 1068
|
|
File "<frozen importlib._bootstrap>", line 619
|
|
File "<frozen importlib._bootstrap>", line 1581
|
|
File "<frozen importlib._bootstrap>", line 1614
|
|
File "/usr/lib/python3.4/doctest.py", line 101
|
|
import pdb
|
|
File "<frozen importlib._bootstrap>", line 284
|
|
File "<frozen importlib._bootstrap>", line 938
|
|
File "<frozen importlib._bootstrap>", line 1068
|
|
File "<frozen importlib._bootstrap>", line 619
|
|
File "<frozen importlib._bootstrap>", line 1581
|
|
File "<frozen importlib._bootstrap>", line 1614
|
|
File "/usr/lib/python3.4/test/support/__init__.py", line 1728
|
|
import doctest
|
|
File "/usr/lib/python3.4/test/test_pickletools.py", line 21
|
|
support.run_doctest(pickletools)
|
|
File "/usr/lib/python3.4/test/regrtest.py", line 1276
|
|
test_runner()
|
|
File "/usr/lib/python3.4/test/regrtest.py", line 976
|
|
display_failure=not verbose)
|
|
File "/usr/lib/python3.4/test/regrtest.py", line 761
|
|
match_tests=ns.match_tests)
|
|
File "/usr/lib/python3.4/test/regrtest.py", line 1563
|
|
main()
|
|
File "/usr/lib/python3.4/test/__main__.py", line 3
|
|
regrtest.main_in_temp_cwd()
|
|
File "/usr/lib/python3.4/runpy.py", line 73
|
|
exec(code, run_globals)
|
|
File "/usr/lib/python3.4/runpy.py", line 160
|
|
"__main__", fname, loader, pkg_name)
|
|
|
|
We can see that the most memory was allocated in the :mod:`importlib` module to
|
|
load data (bytecode and constants) from modules: ``870.1 KiB``. The traceback is
|
|
where the :mod:`importlib` loaded data most recently: on the ``import pdb``
|
|
line of the :mod:`doctest` module. The traceback may change if a new module is
|
|
loaded.
|
|
|
|
|
|
Pretty top
|
|
^^^^^^^^^^
|
|
|
|
Code to display the 10 lines allocating the most memory with a pretty output,
|
|
ignoring ``<frozen importlib._bootstrap>`` and ``<unknown>`` files::
|
|
|
|
import linecache
|
|
import os
|
|
import tracemalloc
|
|
|
|
def display_top(snapshot, key_type='lineno', limit=10):
|
|
snapshot = snapshot.filter_traces((
|
|
tracemalloc.Filter(False, "<frozen importlib._bootstrap>"),
|
|
tracemalloc.Filter(False, "<unknown>"),
|
|
))
|
|
top_stats = snapshot.statistics(key_type)
|
|
|
|
print("Top %s lines" % limit)
|
|
for index, stat in enumerate(top_stats[:limit], 1):
|
|
frame = stat.traceback[0]
|
|
print("#%s: %s:%s: %.1f KiB"
|
|
% (index, frame.filename, frame.lineno, stat.size / 1024))
|
|
line = linecache.getline(frame.filename, frame.lineno).strip()
|
|
if line:
|
|
print(' %s' % line)
|
|
|
|
other = top_stats[limit:]
|
|
if other:
|
|
size = sum(stat.size for stat in other)
|
|
print("%s other: %.1f KiB" % (len(other), size / 1024))
|
|
total = sum(stat.size for stat in top_stats)
|
|
print("Total allocated size: %.1f KiB" % (total / 1024))
|
|
|
|
tracemalloc.start()
|
|
|
|
# ... run your application ...
|
|
|
|
snapshot = tracemalloc.take_snapshot()
|
|
display_top(snapshot)
|
|
|
|
Example of output of the Python test suite::
|
|
|
|
Top 10 lines
|
|
#1: Lib/base64.py:414: 419.8 KiB
|
|
_b85chars2 = [(a + b) for a in _b85chars for b in _b85chars]
|
|
#2: Lib/base64.py:306: 419.8 KiB
|
|
_a85chars2 = [(a + b) for a in _a85chars for b in _a85chars]
|
|
#3: collections/__init__.py:368: 293.6 KiB
|
|
exec(class_definition, namespace)
|
|
#4: Lib/abc.py:133: 115.2 KiB
|
|
cls = super().__new__(mcls, name, bases, namespace)
|
|
#5: unittest/case.py:574: 103.1 KiB
|
|
testMethod()
|
|
#6: Lib/linecache.py:127: 95.4 KiB
|
|
lines = fp.readlines()
|
|
#7: urllib/parse.py:476: 71.8 KiB
|
|
for a in _hexdig for b in _hexdig}
|
|
#8: <string>:5: 62.0 KiB
|
|
#9: Lib/_weakrefset.py:37: 60.0 KiB
|
|
self.data = set()
|
|
#10: Lib/base64.py:142: 59.8 KiB
|
|
_b32tab2 = [a + b for a in _b32tab for b in _b32tab]
|
|
6220 other: 3602.8 KiB
|
|
Total allocated size: 5303.1 KiB
|
|
|
|
See :meth:`Snapshot.statistics` for more options.
|
|
|
|
Record the current and peak size of all traced memory blocks
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
The following code computes two sums like ``0 + 1 + 2 + ...`` inefficiently, by
|
|
creating a list of those numbers. This list consumes a lot of memory
|
|
temporarily. We can use :func:`get_traced_memory` and :func:`reset_peak` to
|
|
observe the small memory usage after the sum is computed as well as the peak
|
|
memory usage during the computations::
|
|
|
|
import tracemalloc
|
|
|
|
tracemalloc.start()
|
|
|
|
# Example code: compute a sum with a large temporary list
|
|
large_sum = sum(list(range(100000)))
|
|
|
|
first_size, first_peak = tracemalloc.get_traced_memory()
|
|
|
|
tracemalloc.reset_peak()
|
|
|
|
# Example code: compute a sum with a small temporary list
|
|
small_sum = sum(list(range(1000)))
|
|
|
|
second_size, second_peak = tracemalloc.get_traced_memory()
|
|
|
|
print(f"{first_size=}, {first_peak=}")
|
|
print(f"{second_size=}, {second_peak=}")
|
|
|
|
Output::
|
|
|
|
first_size=664, first_peak=3592984
|
|
second_size=804, second_peak=29704
|
|
|
|
Using :func:`reset_peak` ensured we could accurately record the peak during the
|
|
computation of ``small_sum``, even though it is much smaller than the overall
|
|
peak size of memory blocks since the :func:`start` call. Without the call to
|
|
:func:`reset_peak`, ``second_peak`` would still be the peak from the
|
|
computation ``large_sum`` (that is, equal to ``first_peak``). In this case,
|
|
both peaks are much higher than the final memory usage, and which suggests we
|
|
could optimise (by removing the unnecessary call to :class:`list`, and writing
|
|
``sum(range(...))``).
|
|
|
|
API
|
|
---
|
|
|
|
Functions
|
|
^^^^^^^^^
|
|
|
|
.. function:: clear_traces()
|
|
|
|
Clear traces of memory blocks allocated by Python.
|
|
|
|
See also :func:`stop`.
|
|
|
|
|
|
.. function:: get_object_traceback(obj)
|
|
|
|
Get the traceback where the Python object *obj* was allocated.
|
|
Return a :class:`Traceback` instance, or ``None`` if the :mod:`tracemalloc`
|
|
module is not tracing memory allocations or did not trace the allocation of
|
|
the object.
|
|
|
|
See also :func:`gc.get_referrers` and :func:`sys.getsizeof` functions.
|
|
|
|
|
|
.. function:: get_traceback_limit()
|
|
|
|
Get the maximum number of frames stored in the traceback of a trace.
|
|
|
|
The :mod:`tracemalloc` module must be tracing memory allocations to
|
|
get the limit, otherwise an exception is raised.
|
|
|
|
The limit is set by the :func:`start` function.
|
|
|
|
|
|
.. function:: get_traced_memory()
|
|
|
|
Get the current size and peak size of memory blocks traced by the
|
|
:mod:`tracemalloc` module as a tuple: ``(current: int, peak: int)``.
|
|
|
|
|
|
.. function:: reset_peak()
|
|
|
|
Set the peak size of memory blocks traced by the :mod:`tracemalloc` module
|
|
to the current size.
|
|
|
|
Do nothing if the :mod:`tracemalloc` module is not tracing memory
|
|
allocations.
|
|
|
|
This function only modifies the recorded peak size, and does not modify or
|
|
clear any traces, unlike :func:`clear_traces`. Snapshots taken with
|
|
:func:`take_snapshot` before a call to :func:`reset_peak` can be
|
|
meaningfully compared to snapshots taken after the call.
|
|
|
|
See also :func:`get_traced_memory`.
|
|
|
|
.. versionadded:: 3.9
|
|
|
|
|
|
.. function:: get_tracemalloc_memory()
|
|
|
|
Get the memory usage in bytes of the :mod:`tracemalloc` module used to store
|
|
traces of memory blocks.
|
|
Return an :class:`int`.
|
|
|
|
|
|
.. function:: is_tracing()
|
|
|
|
``True`` if the :mod:`tracemalloc` module is tracing Python memory
|
|
allocations, ``False`` otherwise.
|
|
|
|
See also :func:`start` and :func:`stop` functions.
|
|
|
|
|
|
.. function:: start(nframe: int=1)
|
|
|
|
Start tracing Python memory allocations: install hooks on Python memory
|
|
allocators. Collected tracebacks of traces will be limited to *nframe*
|
|
frames. By default, a trace of a memory block only stores the most recent
|
|
frame: the limit is ``1``. *nframe* must be greater or equal to ``1``.
|
|
|
|
You can still read the original number of total frames that composed the
|
|
traceback by looking at the :attr:`Traceback.total_nframe` attribute.
|
|
|
|
Storing more than ``1`` frame is only useful to compute statistics grouped
|
|
by ``'traceback'`` or to compute cumulative statistics: see the
|
|
:meth:`Snapshot.compare_to` and :meth:`Snapshot.statistics` methods.
|
|
|
|
Storing more frames increases the memory and CPU overhead of the
|
|
:mod:`tracemalloc` module. Use the :func:`get_tracemalloc_memory` function
|
|
to measure how much memory is used by the :mod:`tracemalloc` module.
|
|
|
|
The :envvar:`PYTHONTRACEMALLOC` environment variable
|
|
(``PYTHONTRACEMALLOC=NFRAME``) and the :option:`-X` ``tracemalloc=NFRAME``
|
|
command line option can be used to start tracing at startup.
|
|
|
|
See also :func:`stop`, :func:`is_tracing` and :func:`get_traceback_limit`
|
|
functions.
|
|
|
|
|
|
.. function:: stop()
|
|
|
|
Stop tracing Python memory allocations: uninstall hooks on Python memory
|
|
allocators. Also clears all previously collected traces of memory blocks
|
|
allocated by Python.
|
|
|
|
Call :func:`take_snapshot` function to take a snapshot of traces before
|
|
clearing them.
|
|
|
|
See also :func:`start`, :func:`is_tracing` and :func:`clear_traces`
|
|
functions.
|
|
|
|
|
|
.. function:: take_snapshot()
|
|
|
|
Take a snapshot of traces of memory blocks allocated by Python. Return a new
|
|
:class:`Snapshot` instance.
|
|
|
|
The snapshot does not include memory blocks allocated before the
|
|
:mod:`tracemalloc` module started to trace memory allocations.
|
|
|
|
Tracebacks of traces are limited to :func:`get_traceback_limit` frames. Use
|
|
the *nframe* parameter of the :func:`start` function to store more frames.
|
|
|
|
The :mod:`tracemalloc` module must be tracing memory allocations to take a
|
|
snapshot, see the :func:`start` function.
|
|
|
|
See also the :func:`get_object_traceback` function.
|
|
|
|
|
|
DomainFilter
|
|
^^^^^^^^^^^^
|
|
|
|
.. class:: DomainFilter(inclusive: bool, domain: int)
|
|
|
|
Filter traces of memory blocks by their address space (domain).
|
|
|
|
.. versionadded:: 3.6
|
|
|
|
.. attribute:: inclusive
|
|
|
|
If *inclusive* is ``True`` (include), match memory blocks allocated
|
|
in the address space :attr:`domain`.
|
|
|
|
If *inclusive* is ``False`` (exclude), match memory blocks not allocated
|
|
in the address space :attr:`domain`.
|
|
|
|
.. attribute:: domain
|
|
|
|
Address space of a memory block (``int``). Read-only property.
|
|
|
|
|
|
Filter
|
|
^^^^^^
|
|
|
|
.. class:: Filter(inclusive: bool, filename_pattern: str, lineno: int=None, all_frames: bool=False, domain: int=None)
|
|
|
|
Filter on traces of memory blocks.
|
|
|
|
See the :func:`fnmatch.fnmatch` function for the syntax of
|
|
*filename_pattern*. The ``'.pyc'`` file extension is
|
|
replaced with ``'.py'``.
|
|
|
|
Examples:
|
|
|
|
* ``Filter(True, subprocess.__file__)`` only includes traces of the
|
|
:mod:`subprocess` module
|
|
* ``Filter(False, tracemalloc.__file__)`` excludes traces of the
|
|
:mod:`tracemalloc` module
|
|
* ``Filter(False, "<unknown>")`` excludes empty tracebacks
|
|
|
|
|
|
.. versionchanged:: 3.5
|
|
The ``'.pyo'`` file extension is no longer replaced with ``'.py'``.
|
|
|
|
.. versionchanged:: 3.6
|
|
Added the :attr:`domain` attribute.
|
|
|
|
|
|
.. attribute:: domain
|
|
|
|
Address space of a memory block (``int`` or ``None``).
|
|
|
|
tracemalloc uses the domain ``0`` to trace memory allocations made by
|
|
Python. C extensions can use other domains to trace other resources.
|
|
|
|
.. attribute:: inclusive
|
|
|
|
If *inclusive* is ``True`` (include), only match memory blocks allocated
|
|
in a file with a name matching :attr:`filename_pattern` at line number
|
|
:attr:`lineno`.
|
|
|
|
If *inclusive* is ``False`` (exclude), ignore memory blocks allocated in
|
|
a file with a name matching :attr:`filename_pattern` at line number
|
|
:attr:`lineno`.
|
|
|
|
.. attribute:: lineno
|
|
|
|
Line number (``int``) of the filter. If *lineno* is ``None``, the filter
|
|
matches any line number.
|
|
|
|
.. attribute:: filename_pattern
|
|
|
|
Filename pattern of the filter (``str``). Read-only property.
|
|
|
|
.. attribute:: all_frames
|
|
|
|
If *all_frames* is ``True``, all frames of the traceback are checked. If
|
|
*all_frames* is ``False``, only the most recent frame is checked.
|
|
|
|
This attribute has no effect if the traceback limit is ``1``. See the
|
|
:func:`get_traceback_limit` function and :attr:`Snapshot.traceback_limit`
|
|
attribute.
|
|
|
|
|
|
Frame
|
|
^^^^^
|
|
|
|
.. class:: Frame
|
|
|
|
Frame of a traceback.
|
|
|
|
The :class:`Traceback` class is a sequence of :class:`Frame` instances.
|
|
|
|
.. attribute:: filename
|
|
|
|
Filename (``str``).
|
|
|
|
.. attribute:: lineno
|
|
|
|
Line number (``int``).
|
|
|
|
|
|
Snapshot
|
|
^^^^^^^^
|
|
|
|
.. class:: Snapshot
|
|
|
|
Snapshot of traces of memory blocks allocated by Python.
|
|
|
|
The :func:`take_snapshot` function creates a snapshot instance.
|
|
|
|
.. method:: compare_to(old_snapshot: Snapshot, key_type: str, cumulative: bool=False)
|
|
|
|
Compute the differences with an old snapshot. Get statistics as a sorted
|
|
list of :class:`StatisticDiff` instances grouped by *key_type*.
|
|
|
|
See the :meth:`Snapshot.statistics` method for *key_type* and *cumulative*
|
|
parameters.
|
|
|
|
The result is sorted from the biggest to the smallest by: absolute value
|
|
of :attr:`StatisticDiff.size_diff`, :attr:`StatisticDiff.size`, absolute
|
|
value of :attr:`StatisticDiff.count_diff`, :attr:`Statistic.count` and
|
|
then by :attr:`StatisticDiff.traceback`.
|
|
|
|
|
|
.. method:: dump(filename)
|
|
|
|
Write the snapshot into a file.
|
|
|
|
Use :meth:`load` to reload the snapshot.
|
|
|
|
|
|
.. method:: filter_traces(filters)
|
|
|
|
Create a new :class:`Snapshot` instance with a filtered :attr:`traces`
|
|
sequence, *filters* is a list of :class:`DomainFilter` and
|
|
:class:`Filter` instances. If *filters* is an empty list, return a new
|
|
:class:`Snapshot` instance with a copy of the traces.
|
|
|
|
All inclusive filters are applied at once, a trace is ignored if no
|
|
inclusive filters match it. A trace is ignored if at least one exclusive
|
|
filter matches it.
|
|
|
|
.. versionchanged:: 3.6
|
|
:class:`DomainFilter` instances are now also accepted in *filters*.
|
|
|
|
|
|
.. classmethod:: load(filename)
|
|
|
|
Load a snapshot from a file.
|
|
|
|
See also :meth:`dump`.
|
|
|
|
|
|
.. method:: statistics(key_type: str, cumulative: bool=False)
|
|
|
|
Get statistics as a sorted list of :class:`Statistic` instances grouped
|
|
by *key_type*:
|
|
|
|
===================== ========================
|
|
key_type description
|
|
===================== ========================
|
|
``'filename'`` filename
|
|
``'lineno'`` filename and line number
|
|
``'traceback'`` traceback
|
|
===================== ========================
|
|
|
|
If *cumulative* is ``True``, cumulate size and count of memory blocks of
|
|
all frames of the traceback of a trace, not only the most recent frame.
|
|
The cumulative mode can only be used with *key_type* equals to
|
|
``'filename'`` and ``'lineno'``.
|
|
|
|
The result is sorted from the biggest to the smallest by:
|
|
:attr:`Statistic.size`, :attr:`Statistic.count` and then by
|
|
:attr:`Statistic.traceback`.
|
|
|
|
|
|
.. attribute:: traceback_limit
|
|
|
|
Maximum number of frames stored in the traceback of :attr:`traces`:
|
|
result of the :func:`get_traceback_limit` when the snapshot was taken.
|
|
|
|
.. attribute:: traces
|
|
|
|
Traces of all memory blocks allocated by Python: sequence of
|
|
:class:`Trace` instances.
|
|
|
|
The sequence has an undefined order. Use the :meth:`Snapshot.statistics`
|
|
method to get a sorted list of statistics.
|
|
|
|
|
|
Statistic
|
|
^^^^^^^^^
|
|
|
|
.. class:: Statistic
|
|
|
|
Statistic on memory allocations.
|
|
|
|
:func:`Snapshot.statistics` returns a list of :class:`Statistic` instances.
|
|
|
|
See also the :class:`StatisticDiff` class.
|
|
|
|
.. attribute:: count
|
|
|
|
Number of memory blocks (``int``).
|
|
|
|
.. attribute:: size
|
|
|
|
Total size of memory blocks in bytes (``int``).
|
|
|
|
.. attribute:: traceback
|
|
|
|
Traceback where the memory block was allocated, :class:`Traceback`
|
|
instance.
|
|
|
|
|
|
StatisticDiff
|
|
^^^^^^^^^^^^^
|
|
|
|
.. class:: StatisticDiff
|
|
|
|
Statistic difference on memory allocations between an old and a new
|
|
:class:`Snapshot` instance.
|
|
|
|
:func:`Snapshot.compare_to` returns a list of :class:`StatisticDiff`
|
|
instances. See also the :class:`Statistic` class.
|
|
|
|
.. attribute:: count
|
|
|
|
Number of memory blocks in the new snapshot (``int``): ``0`` if
|
|
the memory blocks have been released in the new snapshot.
|
|
|
|
.. attribute:: count_diff
|
|
|
|
Difference of number of memory blocks between the old and the new
|
|
snapshots (``int``): ``0`` if the memory blocks have been allocated in
|
|
the new snapshot.
|
|
|
|
.. attribute:: size
|
|
|
|
Total size of memory blocks in bytes in the new snapshot (``int``):
|
|
``0`` if the memory blocks have been released in the new snapshot.
|
|
|
|
.. attribute:: size_diff
|
|
|
|
Difference of total size of memory blocks in bytes between the old and
|
|
the new snapshots (``int``): ``0`` if the memory blocks have been
|
|
allocated in the new snapshot.
|
|
|
|
.. attribute:: traceback
|
|
|
|
Traceback where the memory blocks were allocated, :class:`Traceback`
|
|
instance.
|
|
|
|
|
|
Trace
|
|
^^^^^
|
|
|
|
.. class:: Trace
|
|
|
|
Trace of a memory block.
|
|
|
|
The :attr:`Snapshot.traces` attribute is a sequence of :class:`Trace`
|
|
instances.
|
|
|
|
.. versionchanged:: 3.6
|
|
Added the :attr:`domain` attribute.
|
|
|
|
.. attribute:: domain
|
|
|
|
Address space of a memory block (``int``). Read-only property.
|
|
|
|
tracemalloc uses the domain ``0`` to trace memory allocations made by
|
|
Python. C extensions can use other domains to trace other resources.
|
|
|
|
.. attribute:: size
|
|
|
|
Size of the memory block in bytes (``int``).
|
|
|
|
.. attribute:: traceback
|
|
|
|
Traceback where the memory block was allocated, :class:`Traceback`
|
|
instance.
|
|
|
|
|
|
Traceback
|
|
^^^^^^^^^
|
|
|
|
.. class:: Traceback
|
|
|
|
Sequence of :class:`Frame` instances sorted from the oldest frame to the
|
|
most recent frame.
|
|
|
|
A traceback contains at least ``1`` frame. If the ``tracemalloc`` module
|
|
failed to get a frame, the filename ``"<unknown>"`` at line number ``0`` is
|
|
used.
|
|
|
|
When a snapshot is taken, tracebacks of traces are limited to
|
|
:func:`get_traceback_limit` frames. See the :func:`take_snapshot` function.
|
|
The original number of frames of the traceback is stored in the
|
|
:attr:`Traceback.total_nframe` attribute. That allows to know if a traceback
|
|
has been truncated by the traceback limit.
|
|
|
|
The :attr:`Trace.traceback` attribute is an instance of :class:`Traceback`
|
|
instance.
|
|
|
|
.. versionchanged:: 3.7
|
|
Frames are now sorted from the oldest to the most recent, instead of most recent to oldest.
|
|
|
|
.. attribute:: total_nframe
|
|
|
|
Total number of frames that composed the traceback before truncation.
|
|
This attribute can be set to ``None`` if the information is not
|
|
available.
|
|
|
|
.. versionchanged:: 3.9
|
|
The :attr:`Traceback.total_nframe` attribute was added.
|
|
|
|
.. method:: format(limit=None, most_recent_first=False)
|
|
|
|
Format the traceback as a list of lines. Use the :mod:`linecache` module to
|
|
retrieve lines from the source code. If *limit* is set, format the *limit*
|
|
most recent frames if *limit* is positive. Otherwise, format the
|
|
``abs(limit)`` oldest frames. If *most_recent_first* is ``True``, the order
|
|
of the formatted frames is reversed, returning the most recent frame first
|
|
instead of last.
|
|
|
|
Similar to the :func:`traceback.format_tb` function, except that
|
|
:meth:`.format` does not include newlines.
|
|
|
|
Example::
|
|
|
|
print("Traceback (most recent call first):")
|
|
for line in traceback:
|
|
print(line)
|
|
|
|
Output::
|
|
|
|
Traceback (most recent call first):
|
|
File "test.py", line 9
|
|
obj = Object()
|
|
File "test.py", line 12
|
|
tb = tracemalloc.get_object_traceback(f())
|