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 <section id="module-tracemalloc">
<h1><a class="reference internal" href="#module-tracemalloc" title="tracemalloc: Trace memory allocations."><code class="xref py py-mod docutils literal notranslate">tracemalloc</code></a> — Trace memory allocations<a class="headerlink" href="#module-tracemalloc" title="Permalink to this headline">¶</a></h1>
<div class="versionadded">
New in version 3.4.
</div>
Source code: <a class="reference external" href="https://github.com/python/cpython/tree/3.10/Lib/tracemalloc.py">Lib/tracemalloc.py</a>
<hr class="docutils" />
The tracemalloc module is a debug tool to trace memory blocks allocated by
Python. It provides the following information:
<ul class="simple">
<li>Traceback where an object was allocated</li>
<li>Statistics on allocated memory blocks per filename and per line number:
total size, number and average size of allocated memory blocks</li>
<li>Compute the differences between two snapshots to detect memory leaks</li>
</ul>
To trace most memory blocks allocated by Python, the module should be started
as early as possible by setting the <a class="reference internal" href="../using/cmdline.html#envvar-PYTHONTRACEMALLOC"><code class="xref std std-envvar docutils literal notranslate">PYTHONTRACEMALLOC</code></a> environment
variable to <code class="docutils literal notranslate">1</code>, or by using <a class="reference internal" href="../using/cmdline.html#cmdoption-X"><code class="xref std std-option docutils literal notranslate">-X</code></a> <code class="docutils literal notranslate">tracemalloc</code> command line
option. The <a class="reference internal" href="#tracemalloc.start" title="tracemalloc.start"><code class="xref py py-func docutils literal notranslate">tracemalloc.start()</code></a> 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
<a class="reference internal" href="../using/cmdline.html#envvar-PYTHONTRACEMALLOC"><code class="xref std std-envvar docutils literal notranslate">PYTHONTRACEMALLOC</code></a> environment variable to <code class="docutils literal notranslate">25</code>, or use the
<a class="reference internal" href="../using/cmdline.html#cmdoption-X"><code class="xref std std-option docutils literal notranslate">-X</code></a> <code class="docutils literal notranslate">tracemalloc=25</code> command line option.
<section id="examples">
<h2>Examples<a class="headerlink" href="#examples" title="Permalink to this headline">¶</a></h2>
<section id="display-the-top-10">
<h3>Display the top 10<a class="headerlink" href="#display-the-top-10" title="Permalink to this headline">¶</a></h3>
Display the 10 files allocating the most memory:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>import tracemalloc

tracemalloc.start()

# ... run your application ...

print(&quot;[ Top 10 ]&quot;)
for stat in top_stats[:10]:
 print(stat)
</pre></div>
</div>
Example of output of the Python test suite:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>[ Top 10 ]
&lt;frozen importlib._bootstrap&gt;:716: size=4855 KiB, count=39328, average=126 B
&lt;frozen importlib._bootstrap&gt;: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
&lt;frozen importlib._bootstrap&gt;:1446: size=70.4 KiB, count=911, average=79 B
&lt;frozen importlib._bootstrap&gt;:1454: size=52.0 KiB, count=25, average=2131 B
&lt;string&gt;: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
</pre></div>
</div>
We can see that Python loaded <code class="docutils literal notranslate">4855 KiB</code> data (bytecode and constants) from
modules and that the <a class="reference internal" href="collections.html#module-collections" title="collections: Container datatypes"><code class="xref py py-mod docutils literal notranslate">collections</code></a> module allocated <code class="docutils literal notranslate">244 KiB</code> to build
<a class="reference internal" href="collections.html#collections.namedtuple" title="collections.namedtuple"><code class="xref py py-class docutils literal notranslate">namedtuple</code></a> types.
See <a class="reference internal" href="#tracemalloc.Snapshot.statistics" title="tracemalloc.Snapshot.statistics"><code class="xref py py-meth docutils literal notranslate">Snapshot.statistics()</code></a> for more options.
</section>
<section id="compute-differences">
<h3>Compute differences<a class="headerlink" href="#compute-differences" title="Permalink to this headline">¶</a></h3>
Take two snapshots and display the differences:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>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, &#39;lineno&#39;)

print(&quot;[ Top 10 differences ]&quot;)
for stat in top_stats[:10]:
 print(stat)
</pre></div>
</div>
Example of output before/after running some tests of the Python test suite:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>[ Top 10 differences ]
&lt;frozen importlib._bootstrap&gt;: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
&lt;frozen importlib._bootstrap&gt;: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
</pre></div>
</div>
We can see that Python has loaded <code class="docutils literal notranslate">8173 KiB</code> of module data (bytecode and
constants), and that this is <code class="docutils literal notranslate">4428 KiB</code> more than had been loaded before the
tests, when the previous snapshot was taken. Similarly, the <a class="reference internal" href="linecache.html#module-linecache" title="linecache: Provides random access to individual lines from text files."><code class="xref py py-mod docutils literal notranslate">linecache</code></a>
module has cached <code class="docutils literal notranslate">940 KiB</code> 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 <a class="reference internal" href="#tracemalloc.Snapshot.dump" title="tracemalloc.Snapshot.dump"><code class="xref py py-meth docutils literal notranslate">Snapshot.dump()</code></a> method to analyze the snapshot offline. Then use the
<a class="reference internal" href="#tracemalloc.Snapshot.load" title="tracemalloc.Snapshot.load"><code class="xref py py-meth docutils literal notranslate">Snapshot.load()</code></a> method reload the snapshot.
</section>
<section id="get-the-traceback-of-a-memory-block">
<h3>Get the traceback of a memory block<a class="headerlink" href="#get-the-traceback-of-a-memory-block" title="Permalink to this headline">¶</a></h3>
Code to display the traceback of the biggest memory block:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>import tracemalloc

# Store 25 frames
tracemalloc.start(25)

# ... run your application ...

# pick the biggest memory block
stat = top_stats[0]
print(&quot;%s memory blocks: %.1f KiB&quot; % (stat.count, stat.size / 1024))
for line in stat.traceback.format():
 print(line)
</pre></div>
</div>
Example of output of the Python test suite (traceback limited to 25 frames):
<div class="highlight-python3 notranslate"><div class="highlight"><pre>903 memory blocks: 870.1 KiB
 File &quot;&lt;frozen importlib._bootstrap&gt;&quot;, line 716
 File &quot;&lt;frozen importlib._bootstrap&gt;&quot;, line 1036
 File &quot;&lt;frozen importlib._bootstrap&gt;&quot;, line 934
 File &quot;&lt;frozen importlib._bootstrap&gt;&quot;, line 1068
 File &quot;&lt;frozen importlib._bootstrap&gt;&quot;, line 619
 File &quot;&lt;frozen importlib._bootstrap&gt;&quot;, line 1581
 File &quot;&lt;frozen importlib._bootstrap&gt;&quot;, line 1614
 File &quot;/usr/lib/python3.4/doctest.py&quot;, line 101
 import pdb
 File &quot;&lt;frozen importlib._bootstrap&gt;&quot;, line 284
 File &quot;&lt;frozen importlib._bootstrap&gt;&quot;, line 938
 File &quot;&lt;frozen importlib._bootstrap&gt;&quot;, line 1068
 File &quot;&lt;frozen importlib._bootstrap&gt;&quot;, line 619
 File &quot;&lt;frozen importlib._bootstrap&gt;&quot;, line 1581
 File &quot;&lt;frozen importlib._bootstrap&gt;&quot;, line 1614
 File &quot;/usr/lib/python3.4/test/support/__init__.py&quot;, line 1728
 import doctest
 File &quot;/usr/lib/python3.4/test/test_pickletools.py&quot;, line 21
 support.run_doctest(pickletools)
 File &quot;/usr/lib/python3.4/test/regrtest.py&quot;, line 1276
 test_runner()
 File &quot;/usr/lib/python3.4/test/regrtest.py&quot;, line 976
 display_failure=not verbose)
 File &quot;/usr/lib/python3.4/test/regrtest.py&quot;, line 761
 match_tests=ns.match_tests)
 File &quot;/usr/lib/python3.4/test/regrtest.py&quot;, line 1563
 main()
 File &quot;/usr/lib/python3.4/test/__main__.py&quot;, line 3
 regrtest.main_in_temp_cwd()
 File &quot;/usr/lib/python3.4/runpy.py&quot;, line 73
 exec(code, run_globals)
 File &quot;/usr/lib/python3.4/runpy.py&quot;, line 160
 &quot;__main__&quot;, fname, loader, pkg_name)
</pre></div>
</div>
We can see that the most memory was allocated in the <a class="reference internal" href="importlib.html#module-importlib" title="importlib: The implementation of the import machinery."><code class="xref py py-mod docutils literal notranslate">importlib</code></a> module to
load data (bytecode and constants) from modules: <code class="docutils literal notranslate">870.1 KiB</code>. The traceback is
where the <a class="reference internal" href="importlib.html#module-importlib" title="importlib: The implementation of the import machinery."><code class="xref py py-mod docutils literal notranslate">importlib</code></a> loaded data most recently: on the <code class="docutils literal notranslate">import pdb</code>
line of the <a class="reference internal" href="doctest.html#module-doctest" title="doctest: Test pieces of code within docstrings."><code class="xref py py-mod docutils literal notranslate">doctest</code></a> module. The traceback may change if a new module is
loaded.
</section>
<section id="pretty-top">
<h3>Pretty top<a class="headerlink" href="#pretty-top" title="Permalink to this headline">¶</a></h3>
Code to display the 10 lines allocating the most memory with a pretty output,
ignoring <code class="docutils literal notranslate">&lt;frozen importlib._bootstrap&gt;</code> and <code class="docutils literal notranslate">&lt;unknown&gt;</code> files:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>import linecache
import os
import tracemalloc

def display_top(snapshot, key_type=&#39;lineno&#39;, limit=10):
 snapshot = snapshot.filter_traces((
 tracemalloc.Filter(False, &quot;&lt;frozen importlib._bootstrap&gt;&quot;),
 tracemalloc.Filter(False, &quot;&lt;unknown&gt;&quot;),
 ))
 top_stats = snapshot.statistics(key_type)

print(&quot;Top %s lines&quot; % limit)
 for index, stat in enumerate(top_stats[:limit], 1):
 frame = stat.traceback[0]
 print(&quot;#%s: %s:%s: %.1f KiB&quot;
 % (index, frame.filename, frame.lineno, stat.size / 1024))
 line = linecache.getline(frame.filename, frame.lineno).strip()
 if line:
 print(&#39; %s&#39; % line)

other = top_stats[limit:]
 if other:
 size = sum(stat.size for stat in other)
 print(&quot;%s other: %.1f KiB&quot; % (len(other), size / 1024))
 total = sum(stat.size for stat in top_stats)
 print(&quot;Total allocated size: %.1f KiB&quot; % (total / 1024))

tracemalloc.start()

# ... run your application ...

snapshot = tracemalloc.take_snapshot()
display_top(snapshot)
</pre></div>
</div>
Example of output of the Python test suite:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>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: &lt;string&gt;: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
</pre></div>
</div>
See <a class="reference internal" href="#tracemalloc.Snapshot.statistics" title="tracemalloc.Snapshot.statistics"><code class="xref py py-meth docutils literal notranslate">Snapshot.statistics()</code></a> for more options.
<section id="record-the-current-and-peak-size-of-all-traced-memory-blocks">
<h4>Record the current and peak size of all traced memory blocks<a class="headerlink" href="#record-the-current-and-peak-size-of-all-traced-memory-blocks" title="Permalink to this headline">¶</a></h4>
The following code computes two sums like <code class="docutils literal notranslate">0 + 1 + 2 + ...</code> inefficiently, by
creating a list of those numbers. This list consumes a lot of memory
temporarily. We can use <a class="reference internal" href="#tracemalloc.get_traced_memory" title="tracemalloc.get_traced_memory"><code class="xref py py-func docutils literal notranslate">get_traced_memory()</code></a> and <a class="reference internal" href="#tracemalloc.reset_peak" title="tracemalloc.reset_peak"><code class="xref py py-func docutils literal notranslate">reset_peak()</code></a> to
observe the small memory usage after the sum is computed as well as the peak
memory usage during the computations:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>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&quot;{first_size=}, {first_peak=}&quot;)
print(f&quot;{second_size=}, {second_peak=}&quot;)
</pre></div>
</div>
Output:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>first_size=664, first_peak=3592984
second_size=804, second_peak=29704
</pre></div>
</div>
Using <a class="reference internal" href="#tracemalloc.reset_peak" title="tracemalloc.reset_peak"><code class="xref py py-func docutils literal notranslate">reset_peak()</code></a> ensured we could accurately record the peak during the
computation of <code class="docutils literal notranslate">small_sum</code>, even though it is much smaller than the overall
peak size of memory blocks since the <a class="reference internal" href="#tracemalloc.start" title="tracemalloc.start"><code class="xref py py-func docutils literal notranslate">start()</code></a> call. Without the call to
<a class="reference internal" href="#tracemalloc.reset_peak" title="tracemalloc.reset_peak"><code class="xref py py-func docutils literal notranslate">reset_peak()</code></a>, <code class="docutils literal notranslate">second_peak</code> would still be the peak from the
computation <code class="docutils literal notranslate">large_sum</code> (that is, equal to <code class="docutils literal notranslate">first_peak</code>). 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 <a class="reference internal" href="stdtypes.html#list" title="list"><code class="xref py py-class docutils literal notranslate">list</code></a>, and writing
<code class="docutils literal notranslate">sum(range(...))</code>).
</section>
</section>
</section>
<section id="api">
<h2>API<a class="headerlink" href="#api" title="Permalink to this headline">¶</a></h2>
<section id="functions">
<h3>Functions<a class="headerlink" href="#functions" title="Permalink to this headline">¶</a></h3>
<dl class="py function">
<dt class="sig sig-object py" id="tracemalloc.clear_traces">
tracemalloc.clear_traces()<a class="headerlink" href="#tracemalloc.clear_traces" title="Permalink to this definition">¶</a></dt>
<dd>Clear traces of memory blocks allocated by Python.
See also <a class="reference internal" href="#tracemalloc.stop" title="tracemalloc.stop"><code class="xref py py-func docutils literal notranslate">stop()</code></a>.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="tracemalloc.get_object_traceback">
tracemalloc.get_object_traceback(obj)<a class="headerlink" href="#tracemalloc.get_object_traceback" title="Permalink to this definition">¶</a></dt>
<dd>Get the traceback where the Python object obj was allocated.
Return a <a class="reference internal" href="#tracemalloc.Traceback" title="tracemalloc.Traceback"><code class="xref py py-class docutils literal notranslate">Traceback</code></a> instance, or <code class="docutils literal notranslate">None</code> if the <a class="reference internal" href="#module-tracemalloc" title="tracemalloc: Trace memory allocations."><code class="xref py py-mod docutils literal notranslate">tracemalloc</code></a>
module is not tracing memory allocations or did not trace the allocation of
the object.
See also <a class="reference internal" href="gc.html#gc.get_referrers" title="gc.get_referrers"><code class="xref py py-func docutils literal notranslate">gc.get_referrers()</code></a> and <a class="reference internal" href="sys.html#sys.getsizeof" title="sys.getsizeof"><code class="xref py py-func docutils literal notranslate">sys.getsizeof()</code></a> functions.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="tracemalloc.get_traceback_limit">
tracemalloc.get_traceback_limit()<a class="headerlink" href="#tracemalloc.get_traceback_limit" title="Permalink to this definition">¶</a></dt>
<dd>Get the maximum number of frames stored in the traceback of a trace.
The <a class="reference internal" href="#module-tracemalloc" title="tracemalloc: Trace memory allocations."><code class="xref py py-mod docutils literal notranslate">tracemalloc</code></a> module must be tracing memory allocations to
get the limit, otherwise an exception is raised.
The limit is set by the <a class="reference internal" href="#tracemalloc.start" title="tracemalloc.start"><code class="xref py py-func docutils literal notranslate">start()</code></a> function.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="tracemalloc.get_traced_memory">
tracemalloc.get_traced_memory()<a class="headerlink" href="#tracemalloc.get_traced_memory" title="Permalink to this definition">¶</a></dt>
<dd>Get the current size and peak size of memory blocks traced by the
<a class="reference internal" href="#module-tracemalloc" title="tracemalloc: Trace memory allocations."><code class="xref py py-mod docutils literal notranslate">tracemalloc</code></a> module as a tuple: <code class="docutils literal notranslate">(current: int, peak: int)</code>.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="tracemalloc.reset_peak">
tracemalloc.reset_peak()<a class="headerlink" href="#tracemalloc.reset_peak" title="Permalink to this definition">¶</a></dt>
<dd>Set the peak size of memory blocks traced by the <a class="reference internal" href="#module-tracemalloc" title="tracemalloc: Trace memory allocations."><code class="xref py py-mod docutils literal notranslate">tracemalloc</code></a> module
to the current size.
Do nothing if the <a class="reference internal" href="#module-tracemalloc" title="tracemalloc: Trace memory allocations."><code class="xref py py-mod docutils literal notranslate">tracemalloc</code></a> module is not tracing memory
allocations.
This function only modifies the recorded peak size, and does not modify or
clear any traces, unlike <a class="reference internal" href="#tracemalloc.clear_traces" title="tracemalloc.clear_traces"><code class="xref py py-func docutils literal notranslate">clear_traces()</code></a>. Snapshots taken with
<a class="reference internal" href="#tracemalloc.take_snapshot" title="tracemalloc.take_snapshot"><code class="xref py py-func docutils literal notranslate">take_snapshot()</code></a> before a call to <a class="reference internal" href="#tracemalloc.reset_peak" title="tracemalloc.reset_peak"><code class="xref py py-func docutils literal notranslate">reset_peak()</code></a> can be
meaningfully compared to snapshots taken after the call.
See also <a class="reference internal" href="#tracemalloc.get_traced_memory" title="tracemalloc.get_traced_memory"><code class="xref py py-func docutils literal notranslate">get_traced_memory()</code></a>.
<div class="versionadded">
New in version 3.9.
</div>
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="tracemalloc.get_tracemalloc_memory">
tracemalloc.get_tracemalloc_memory()<a class="headerlink" href="#tracemalloc.get_tracemalloc_memory" title="Permalink to this definition">¶</a></dt>
<dd>Get the memory usage in bytes of the <a class="reference internal" href="#module-tracemalloc" title="tracemalloc: Trace memory allocations."><code class="xref py py-mod docutils literal notranslate">tracemalloc</code></a> module used to store
traces of memory blocks.
Return an <a class="reference internal" href="functions.html#int" title="int"><code class="xref py py-class docutils literal notranslate">int</code></a>.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="tracemalloc.is_tracing">
tracemalloc.is_tracing()<a class="headerlink" href="#tracemalloc.is_tracing" title="Permalink to this definition">¶</a></dt>
<dd><code class="docutils literal notranslate">True</code> if the <a class="reference internal" href="#module-tracemalloc" title="tracemalloc: Trace memory allocations."><code class="xref py py-mod docutils literal notranslate">tracemalloc</code></a> module is tracing Python memory
allocations, <code class="docutils literal notranslate">False</code> otherwise.
See also <a class="reference internal" href="#tracemalloc.start" title="tracemalloc.start"><code class="xref py py-func docutils literal notranslate">start()</code></a> and <a class="reference internal" href="#tracemalloc.stop" title="tracemalloc.stop"><code class="xref py py-func docutils literal notranslate">stop()</code></a> functions.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="tracemalloc.start">
tracemalloc.start(nframe: <a class="reference internal" href="functions.html#int" title="int">int</a> = 1)<a class="headerlink" href="#tracemalloc.start" title="Permalink to this definition">¶</a></dt>
<dd>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 <code class="docutils literal notranslate">1</code>. nframe must be greater or equal to <code class="docutils literal notranslate">1</code>.
You can still read the original number of total frames that composed the
traceback by looking at the <a class="reference internal" href="#tracemalloc.Traceback.total_nframe" title="tracemalloc.Traceback.total_nframe"><code class="xref py py-attr docutils literal notranslate">Traceback.total_nframe</code></a> attribute.
Storing more than <code class="docutils literal notranslate">1</code> frame is only useful to compute statistics grouped
by <code class="docutils literal notranslate">'traceback'</code> or to compute cumulative statistics: see the
<a class="reference internal" href="#tracemalloc.Snapshot.compare_to" title="tracemalloc.Snapshot.compare_to"><code class="xref py py-meth docutils literal notranslate">Snapshot.compare_to()</code></a> and <a class="reference internal" href="#tracemalloc.Snapshot.statistics" title="tracemalloc.Snapshot.statistics"><code class="xref py py-meth docutils literal notranslate">Snapshot.statistics()</code></a> methods.
Storing more frames increases the memory and CPU overhead of the
<a class="reference internal" href="#module-tracemalloc" title="tracemalloc: Trace memory allocations."><code class="xref py py-mod docutils literal notranslate">tracemalloc</code></a> module. Use the <a class="reference internal" href="#tracemalloc.get_tracemalloc_memory" title="tracemalloc.get_tracemalloc_memory"><code class="xref py py-func docutils literal notranslate">get_tracemalloc_memory()</code></a> function
to measure how much memory is used by the <a class="reference internal" href="#module-tracemalloc" title="tracemalloc: Trace memory allocations."><code class="xref py py-mod docutils literal notranslate">tracemalloc</code></a> module.
The <a class="reference internal" href="../using/cmdline.html#envvar-PYTHONTRACEMALLOC"><code class="xref std std-envvar docutils literal notranslate">PYTHONTRACEMALLOC</code></a> environment variable
(<code class="docutils literal notranslate">PYTHONTRACEMALLOC=NFRAME</code>) and the <a class="reference internal" href="../using/cmdline.html#cmdoption-X"><code class="xref std std-option docutils literal notranslate">-X</code></a> <code class="docutils literal notranslate">tracemalloc=NFRAME</code>
command line option can be used to start tracing at startup.
See also <a class="reference internal" href="#tracemalloc.stop" title="tracemalloc.stop"><code class="xref py py-func docutils literal notranslate">stop()</code></a>, <a class="reference internal" href="#tracemalloc.is_tracing" title="tracemalloc.is_tracing"><code class="xref py py-func docutils literal notranslate">is_tracing()</code></a> and <a class="reference internal" href="#tracemalloc.get_traceback_limit" title="tracemalloc.get_traceback_limit"><code class="xref py py-func docutils literal notranslate">get_traceback_limit()</code></a>
functions.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="tracemalloc.stop">
tracemalloc.stop()<a class="headerlink" href="#tracemalloc.stop" title="Permalink to this definition">¶</a></dt>
<dd>Stop tracing Python memory allocations: uninstall hooks on Python memory
allocators. Also clears all previously collected traces of memory blocks
allocated by Python.
Call <a class="reference internal" href="#tracemalloc.take_snapshot" title="tracemalloc.take_snapshot"><code class="xref py py-func docutils literal notranslate">take_snapshot()</code></a> function to take a snapshot of traces before
clearing them.
See also <a class="reference internal" href="#tracemalloc.start" title="tracemalloc.start"><code class="xref py py-func docutils literal notranslate">start()</code></a>, <a class="reference internal" href="#tracemalloc.is_tracing" title="tracemalloc.is_tracing"><code class="xref py py-func docutils literal notranslate">is_tracing()</code></a> and <a class="reference internal" href="#tracemalloc.clear_traces" title="tracemalloc.clear_traces"><code class="xref py py-func docutils literal notranslate">clear_traces()</code></a>
functions.
</dd></dl>

<dl class="py function">
<dt class="sig sig-object py" id="tracemalloc.take_snapshot">
tracemalloc.take_snapshot()<a class="headerlink" href="#tracemalloc.take_snapshot" title="Permalink to this definition">¶</a></dt>
<dd>Take a snapshot of traces of memory blocks allocated by Python. Return a new
<a class="reference internal" href="#tracemalloc.Snapshot" title="tracemalloc.Snapshot"><code class="xref py py-class docutils literal notranslate">Snapshot</code></a> instance.
The snapshot does not include memory blocks allocated before the
<a class="reference internal" href="#module-tracemalloc" title="tracemalloc: Trace memory allocations."><code class="xref py py-mod docutils literal notranslate">tracemalloc</code></a> module started to trace memory allocations.
Tracebacks of traces are limited to <a class="reference internal" href="#tracemalloc.get_traceback_limit" title="tracemalloc.get_traceback_limit"><code class="xref py py-func docutils literal notranslate">get_traceback_limit()</code></a> frames. Use
the nframe parameter of the <a class="reference internal" href="#tracemalloc.start" title="tracemalloc.start"><code class="xref py py-func docutils literal notranslate">start()</code></a> function to store more frames.
The <a class="reference internal" href="#module-tracemalloc" title="tracemalloc: Trace memory allocations."><code class="xref py py-mod docutils literal notranslate">tracemalloc</code></a> module must be tracing memory allocations to take a
snapshot, see the <a class="reference internal" href="#tracemalloc.start" title="tracemalloc.start"><code class="xref py py-func docutils literal notranslate">start()</code></a> function.
See also the <a class="reference internal" href="#tracemalloc.get_object_traceback" title="tracemalloc.get_object_traceback"><code class="xref py py-func docutils literal notranslate">get_object_traceback()</code></a> function.
</dd></dl>

</section>
<section id="domainfilter">
<h3>DomainFilter<a class="headerlink" href="#domainfilter" title="Permalink to this headline">¶</a></h3>
<dl class="py class">
<dt class="sig sig-object py" id="tracemalloc.DomainFilter">
class tracemalloc.DomainFilter(inclusive: <a class="reference internal" href="functions.html#bool" title="bool">bool</a>, domain: <a class="reference internal" href="functions.html#int" title="int">int</a>)<a class="headerlink" href="#tracemalloc.DomainFilter" title="Permalink to this definition">¶</a></dt>
<dd>Filter traces of memory blocks by their address space (domain).
<div class="versionadded">
New in version 3.6.
</div>
<dl class="py attribute">
<dt class="sig sig-object py" id="tracemalloc.DomainFilter.inclusive">
inclusive<a class="headerlink" href="#tracemalloc.DomainFilter.inclusive" title="Permalink to this definition">¶</a></dt>
<dd>If inclusive is <code class="docutils literal notranslate">True</code> (include), match memory blocks allocated
in the address space <a class="reference internal" href="#tracemalloc.DomainFilter.domain" title="tracemalloc.DomainFilter.domain"><code class="xref py py-attr docutils literal notranslate">domain</code></a>.
If inclusive is <code class="docutils literal notranslate">False</code> (exclude), match memory blocks not allocated
in the address space <a class="reference internal" href="#tracemalloc.DomainFilter.domain" title="tracemalloc.DomainFilter.domain"><code class="xref py py-attr docutils literal notranslate">domain</code></a>.
</dd></dl>

<dl class="py attribute">
<dt class="sig sig-object py" id="tracemalloc.DomainFilter.domain">
domain<a class="headerlink" href="#tracemalloc.DomainFilter.domain" title="Permalink to this definition">¶</a></dt>
<dd>Address space of a memory block (<code class="docutils literal notranslate">int</code>). Read-only property.
</dd></dl>

</dd></dl>

</section>
<section id="filter">
<h3>Filter<a class="headerlink" href="#filter" title="Permalink to this headline">¶</a></h3>
<dl class="py class">
<dt class="sig sig-object py" id="tracemalloc.Filter">
class tracemalloc.Filter(inclusive: <a class="reference internal" href="functions.html#bool" title="bool">bool</a>, filename_pattern: <a class="reference internal" href="stdtypes.html#str" title="str">str</a>, lineno: <a class="reference internal" href="functions.html#int" title="int">int</a> = None, all_frames: <a class="reference internal" href="functions.html#bool" title="bool">bool</a> = False, domain: <a class="reference internal" href="functions.html#int" title="int">int</a> = None)<a class="headerlink" href="#tracemalloc.Filter" title="Permalink to this definition">¶</a></dt>
<dd>Filter on traces of memory blocks.
See the <a class="reference internal" href="fnmatch.html#fnmatch.fnmatch" title="fnmatch.fnmatch"><code class="xref py py-func docutils literal notranslate">fnmatch.fnmatch()</code></a> function for the syntax of
filename_pattern. The <code class="docutils literal notranslate">'.pyc'</code> file extension is
replaced with <code class="docutils literal notranslate">'.py'</code>.
Examples:
<ul class="simple">
<li><code class="docutils literal notranslate">Filter(True, subprocess.__file__)</code> only includes traces of the
<a class="reference internal" href="subprocess.html#module-subprocess" title="subprocess: Subprocess management."><code class="xref py py-mod docutils literal notranslate">subprocess</code></a> module</li>
<li><code class="docutils literal notranslate">Filter(False, tracemalloc.__file__)</code> excludes traces of the
<a class="reference internal" href="#module-tracemalloc" title="tracemalloc: Trace memory allocations."><code class="xref py py-mod docutils literal notranslate">tracemalloc</code></a> module</li>
<li><code class="docutils literal notranslate">Filter(False, &quot;&lt;unknown&gt;&quot;)</code> excludes empty tracebacks</li>
</ul>
<div class="versionchanged">
Changed in version 3.5: The <code class="docutils literal notranslate">'.pyo'</code> file extension is no longer replaced with <code class="docutils literal notranslate">'.py'</code>.
</div>
<div class="versionchanged">
Changed in version 3.6: Added the <a class="reference internal" href="#tracemalloc.Filter.domain" title="tracemalloc.Filter.domain"><code class="xref py py-attr docutils literal notranslate">domain</code></a> attribute.
</div>
<dl class="py attribute">
<dt class="sig sig-object py" id="tracemalloc.Filter.domain">
domain<a class="headerlink" href="#tracemalloc.Filter.domain" title="Permalink to this definition">¶</a></dt>
<dd>Address space of a memory block (<code class="docutils literal notranslate">int</code> or <code class="docutils literal notranslate">None</code>).
tracemalloc uses the domain <code class="docutils literal notranslate">0</code> to trace memory allocations made by
Python. C extensions can use other domains to trace other resources.
</dd></dl>

<dl class="py attribute">
<dt class="sig sig-object py" id="tracemalloc.Filter.inclusive">
inclusive<a class="headerlink" href="#tracemalloc.Filter.inclusive" title="Permalink to this definition">¶</a></dt>
<dd>If inclusive is <code class="docutils literal notranslate">True</code> (include), only match memory blocks allocated
in a file with a name matching <a class="reference internal" href="#tracemalloc.Filter.filename_pattern" title="tracemalloc.Filter.filename_pattern"><code class="xref py py-attr docutils literal notranslate">filename_pattern</code></a> at line number
<a class="reference internal" href="#tracemalloc.Filter.lineno" title="tracemalloc.Filter.lineno"><code class="xref py py-attr docutils literal notranslate">lineno</code></a>.
If inclusive is <code class="docutils literal notranslate">False</code> (exclude), ignore memory blocks allocated in
a file with a name matching <a class="reference internal" href="#tracemalloc.Filter.filename_pattern" title="tracemalloc.Filter.filename_pattern"><code class="xref py py-attr docutils literal notranslate">filename_pattern</code></a> at line number
<a class="reference internal" href="#tracemalloc.Filter.lineno" title="tracemalloc.Filter.lineno"><code class="xref py py-attr docutils literal notranslate">lineno</code></a>.
</dd></dl>

<dl class="py attribute">
<dt class="sig sig-object py" id="tracemalloc.Filter.lineno">
lineno<a class="headerlink" href="#tracemalloc.Filter.lineno" title="Permalink to this definition">¶</a></dt>
<dd>Line number (<code class="docutils literal notranslate">int</code>) of the filter. If lineno is <code class="docutils literal notranslate">None</code>, the filter
matches any line number.
</dd></dl>

<dl class="py attribute">
<dt class="sig sig-object py" id="tracemalloc.Filter.filename_pattern">
filename_pattern<a class="headerlink" href="#tracemalloc.Filter.filename_pattern" title="Permalink to this definition">¶</a></dt>
<dd>Filename pattern of the filter (<code class="docutils literal notranslate">str</code>). Read-only property.
</dd></dl>

<dl class="py attribute">
<dt class="sig sig-object py" id="tracemalloc.Filter.all_frames">
all_frames<a class="headerlink" href="#tracemalloc.Filter.all_frames" title="Permalink to this definition">¶</a></dt>
<dd>If all_frames is <code class="docutils literal notranslate">True</code>, all frames of the traceback are checked. If
all_frames is <code class="docutils literal notranslate">False</code>, only the most recent frame is checked.
This attribute has no effect if the traceback limit is <code class="docutils literal notranslate">1</code>. See the
<a class="reference internal" href="#tracemalloc.get_traceback_limit" title="tracemalloc.get_traceback_limit"><code class="xref py py-func docutils literal notranslate">get_traceback_limit()</code></a> function and <a class="reference internal" href="#tracemalloc.Snapshot.traceback_limit" title="tracemalloc.Snapshot.traceback_limit"><code class="xref py py-attr docutils literal notranslate">Snapshot.traceback_limit</code></a>
attribute.
</dd></dl>

</dd></dl>

</section>
<section id="frame">
<h3>Frame<a class="headerlink" href="#frame" title="Permalink to this headline">¶</a></h3>
<dl class="py class">
<dt class="sig sig-object py" id="tracemalloc.Frame">
class tracemalloc.Frame<a class="headerlink" href="#tracemalloc.Frame" title="Permalink to this definition">¶</a></dt>
<dd>Frame of a traceback.
The <a class="reference internal" href="#tracemalloc.Traceback" title="tracemalloc.Traceback"><code class="xref py py-class docutils literal notranslate">Traceback</code></a> class is a sequence of <a class="reference internal" href="#tracemalloc.Frame" title="tracemalloc.Frame"><code class="xref py py-class docutils literal notranslate">Frame</code></a> instances.
<dl class="py attribute">
<dt class="sig sig-object py" id="tracemalloc.Frame.filename">
filename<a class="headerlink" href="#tracemalloc.Frame.filename" title="Permalink to this definition">¶</a></dt>
<dd>Filename (<code class="docutils literal notranslate">str</code>).
</dd></dl>

<dl class="py attribute">
<dt class="sig sig-object py" id="tracemalloc.Frame.lineno">
lineno<a class="headerlink" href="#tracemalloc.Frame.lineno" title="Permalink to this definition">¶</a></dt>
<dd>Line number (<code class="docutils literal notranslate">int</code>).
</dd></dl>

</dd></dl>

</section>
<section id="snapshot">
<h3>Snapshot<a class="headerlink" href="#snapshot" title="Permalink to this headline">¶</a></h3>
<dl class="py class">
<dt class="sig sig-object py" id="tracemalloc.Snapshot">
class tracemalloc.Snapshot<a class="headerlink" href="#tracemalloc.Snapshot" title="Permalink to this definition">¶</a></dt>
<dd>Snapshot of traces of memory blocks allocated by Python.
The <a class="reference internal" href="#tracemalloc.take_snapshot" title="tracemalloc.take_snapshot"><code class="xref py py-func docutils literal notranslate">take_snapshot()</code></a> function creates a snapshot instance.
<dl class="py method">
<dt class="sig sig-object py" id="tracemalloc.Snapshot.compare_to">
compare_to(old_snapshot: <a class="reference internal" href="#tracemalloc.Snapshot" title="tracemalloc.Snapshot">Snapshot</a>, key_type: <a class="reference internal" href="stdtypes.html#str" title="str">str</a>, cumulative: <a class="reference internal" href="functions.html#bool" title="bool">bool</a> = False)<a class="headerlink" href="#tracemalloc.Snapshot.compare_to" title="Permalink to this definition">¶</a></dt>
<dd>Compute the differences with an old snapshot. Get statistics as a sorted
list of <a class="reference internal" href="#tracemalloc.StatisticDiff" title="tracemalloc.StatisticDiff"><code class="xref py py-class docutils literal notranslate">StatisticDiff</code></a> instances grouped by key_type.
See the <a class="reference internal" href="#tracemalloc.Snapshot.statistics" title="tracemalloc.Snapshot.statistics"><code class="xref py py-meth docutils literal notranslate">Snapshot.statistics()</code></a> method for key_type and cumulative
parameters.
The result is sorted from the biggest to the smallest by: absolute value
of <a class="reference internal" href="#tracemalloc.StatisticDiff.size_diff" title="tracemalloc.StatisticDiff.size_diff"><code class="xref py py-attr docutils literal notranslate">StatisticDiff.size_diff</code></a>, <a class="reference internal" href="#tracemalloc.StatisticDiff.size" title="tracemalloc.StatisticDiff.size"><code class="xref py py-attr docutils literal notranslate">StatisticDiff.size</code></a>, absolute
value of <a class="reference internal" href="#tracemalloc.StatisticDiff.count_diff" title="tracemalloc.StatisticDiff.count_diff"><code class="xref py py-attr docutils literal notranslate">StatisticDiff.count_diff</code></a>, <a class="reference internal" href="#tracemalloc.Statistic.count" title="tracemalloc.Statistic.count"><code class="xref py py-attr docutils literal notranslate">Statistic.count</code></a> and
then by <a class="reference internal" href="#tracemalloc.StatisticDiff.traceback" title="tracemalloc.StatisticDiff.traceback"><code class="xref py py-attr docutils literal notranslate">StatisticDiff.traceback</code></a>.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="tracemalloc.Snapshot.dump">
dump(filename)<a class="headerlink" href="#tracemalloc.Snapshot.dump" title="Permalink to this definition">¶</a></dt>
<dd>Write the snapshot into a file.
Use <a class="reference internal" href="#tracemalloc.Snapshot.load" title="tracemalloc.Snapshot.load"><code class="xref py py-meth docutils literal notranslate">load()</code></a> to reload the snapshot.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="tracemalloc.Snapshot.filter_traces">
filter_traces(filters)<a class="headerlink" href="#tracemalloc.Snapshot.filter_traces" title="Permalink to this definition">¶</a></dt>
<dd>Create a new <a class="reference internal" href="#tracemalloc.Snapshot" title="tracemalloc.Snapshot"><code class="xref py py-class docutils literal notranslate">Snapshot</code></a> instance with a filtered <a class="reference internal" href="#tracemalloc.Snapshot.traces" title="tracemalloc.Snapshot.traces"><code class="xref py py-attr docutils literal notranslate">traces</code></a>
sequence, filters is a list of <a class="reference internal" href="#tracemalloc.DomainFilter" title="tracemalloc.DomainFilter"><code class="xref py py-class docutils literal notranslate">DomainFilter</code></a> and
<a class="reference internal" href="#tracemalloc.Filter" title="tracemalloc.Filter"><code class="xref py py-class docutils literal notranslate">Filter</code></a> instances. If filters is an empty list, return a new
<a class="reference internal" href="#tracemalloc.Snapshot" title="tracemalloc.Snapshot"><code class="xref py py-class docutils literal notranslate">Snapshot</code></a> 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.
<div class="versionchanged">
Changed in version 3.6: <a class="reference internal" href="#tracemalloc.DomainFilter" title="tracemalloc.DomainFilter"><code class="xref py py-class docutils literal notranslate">DomainFilter</code></a> instances are now also accepted in filters.
</div>
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="tracemalloc.Snapshot.load">
classmethod load(filename)<a class="headerlink" href="#tracemalloc.Snapshot.load" title="Permalink to this definition">¶</a></dt>
<dd>Load a snapshot from a file.
See also <a class="reference internal" href="#tracemalloc.Snapshot.dump" title="tracemalloc.Snapshot.dump"><code class="xref py py-meth docutils literal notranslate">dump()</code></a>.
</dd></dl>

<dl class="py method">
<dt class="sig sig-object py" id="tracemalloc.Snapshot.statistics">
statistics(key_type: <a class="reference internal" href="stdtypes.html#str" title="str">str</a>, cumulative: <a class="reference internal" href="functions.html#bool" title="bool">bool</a> = False)<a class="headerlink" href="#tracemalloc.Snapshot.statistics" title="Permalink to this definition">¶</a></dt>
<dd>Get statistics as a sorted list of <a class="reference internal" href="#tracemalloc.Statistic" title="tracemalloc.Statistic"><code class="xref py py-class docutils literal notranslate">Statistic</code></a> instances grouped
by key_type:
<table class="docutils align-default">
<colgroup>
<col style="width: 47%" />
<col style="width: 53%" />
</colgroup>
<thead>
<tr class="row-odd"><th class="head">key_type</th>
<th class="head">description</th>
</tr>
</thead>
<tbody>
<tr class="row-even"><td><code class="docutils literal notranslate">'filename'</code></td>
<td>filename</td>
</tr>
<tr class="row-odd"><td><code class="docutils literal notranslate">'lineno'</code></td>
<td>filename and line number</td>
</tr>
<tr class="row-even"><td><code class="docutils literal notranslate">'traceback'</code></td>
<td>traceback</td>
</tr>
</tbody>
</table>
If cumulative is <code class="docutils literal notranslate">True</code>, 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
<code class="docutils literal notranslate">'filename'</code> and <code class="docutils literal notranslate">'lineno'</code>.
The result is sorted from the biggest to the smallest by:
<a class="reference internal" href="#tracemalloc.Statistic.size" title="tracemalloc.Statistic.size"><code class="xref py py-attr docutils literal notranslate">Statistic.size</code></a>, <a class="reference internal" href="#tracemalloc.Statistic.count" title="tracemalloc.Statistic.count"><code class="xref py py-attr docutils literal notranslate">Statistic.count</code></a> and then by
<a class="reference internal" href="#tracemalloc.Statistic.traceback" title="tracemalloc.Statistic.traceback"><code class="xref py py-attr docutils literal notranslate">Statistic.traceback</code></a>.
</dd></dl>

<dl class="py attribute">
<dt class="sig sig-object py" id="tracemalloc.Snapshot.traceback_limit">
traceback_limit<a class="headerlink" href="#tracemalloc.Snapshot.traceback_limit" title="Permalink to this definition">¶</a></dt>
<dd>Maximum number of frames stored in the traceback of <a class="reference internal" href="#tracemalloc.Snapshot.traces" title="tracemalloc.Snapshot.traces"><code class="xref py py-attr docutils literal notranslate">traces</code></a>:
result of the <a class="reference internal" href="#tracemalloc.get_traceback_limit" title="tracemalloc.get_traceback_limit"><code class="xref py py-func docutils literal notranslate">get_traceback_limit()</code></a> when the snapshot was taken.
</dd></dl>

<dl class="py attribute">
<dt class="sig sig-object py" id="tracemalloc.Snapshot.traces">
traces<a class="headerlink" href="#tracemalloc.Snapshot.traces" title="Permalink to this definition">¶</a></dt>
<dd>Traces of all memory blocks allocated by Python: sequence of
<a class="reference internal" href="#tracemalloc.Trace" title="tracemalloc.Trace"><code class="xref py py-class docutils literal notranslate">Trace</code></a> instances.
The sequence has an undefined order. Use the <a class="reference internal" href="#tracemalloc.Snapshot.statistics" title="tracemalloc.Snapshot.statistics"><code class="xref py py-meth docutils literal notranslate">Snapshot.statistics()</code></a>
method to get a sorted list of statistics.
</dd></dl>

</dd></dl>

</section>
<section id="statistic">
<h3>Statistic<a class="headerlink" href="#statistic" title="Permalink to this headline">¶</a></h3>
<dl class="py class">
<dt class="sig sig-object py" id="tracemalloc.Statistic">
class tracemalloc.Statistic<a class="headerlink" href="#tracemalloc.Statistic" title="Permalink to this definition">¶</a></dt>
<dd>Statistic on memory allocations.
<a class="reference internal" href="#tracemalloc.Snapshot.statistics" title="tracemalloc.Snapshot.statistics"><code class="xref py py-func docutils literal notranslate">Snapshot.statistics()</code></a> returns a list of <a class="reference internal" href="#tracemalloc.Statistic" title="tracemalloc.Statistic"><code class="xref py py-class docutils literal notranslate">Statistic</code></a> instances.
See also the <a class="reference internal" href="#tracemalloc.StatisticDiff" title="tracemalloc.StatisticDiff"><code class="xref py py-class docutils literal notranslate">StatisticDiff</code></a> class.
<dl class="py attribute">
<dt class="sig sig-object py" id="tracemalloc.Statistic.count">
count<a class="headerlink" href="#tracemalloc.Statistic.count" title="Permalink to this definition">¶</a></dt>
<dd>Number of memory blocks (<code class="docutils literal notranslate">int</code>).
</dd></dl>

<dl class="py attribute">
<dt class="sig sig-object py" id="tracemalloc.Statistic.size">
size<a class="headerlink" href="#tracemalloc.Statistic.size" title="Permalink to this definition">¶</a></dt>
<dd>Total size of memory blocks in bytes (<code class="docutils literal notranslate">int</code>).
</dd></dl>

<dl class="py attribute">
<dt class="sig sig-object py" id="tracemalloc.Statistic.traceback">
traceback<a class="headerlink" href="#tracemalloc.Statistic.traceback" title="Permalink to this definition">¶</a></dt>
<dd>Traceback where the memory block was allocated, <a class="reference internal" href="#tracemalloc.Traceback" title="tracemalloc.Traceback"><code class="xref py py-class docutils literal notranslate">Traceback</code></a>
instance.
</dd></dl>

</dd></dl>

</section>
<section id="statisticdiff">
<h3>StatisticDiff<a class="headerlink" href="#statisticdiff" title="Permalink to this headline">¶</a></h3>
<dl class="py class">
<dt class="sig sig-object py" id="tracemalloc.StatisticDiff">
class tracemalloc.StatisticDiff<a class="headerlink" href="#tracemalloc.StatisticDiff" title="Permalink to this definition">¶</a></dt>
<dd>Statistic difference on memory allocations between an old and a new
<a class="reference internal" href="#tracemalloc.Snapshot" title="tracemalloc.Snapshot"><code class="xref py py-class docutils literal notranslate">Snapshot</code></a> instance.
<a class="reference internal" href="#tracemalloc.Snapshot.compare_to" title="tracemalloc.Snapshot.compare_to"><code class="xref py py-func docutils literal notranslate">Snapshot.compare_to()</code></a> returns a list of <a class="reference internal" href="#tracemalloc.StatisticDiff" title="tracemalloc.StatisticDiff"><code class="xref py py-class docutils literal notranslate">StatisticDiff</code></a>
instances. See also the <a class="reference internal" href="#tracemalloc.Statistic" title="tracemalloc.Statistic"><code class="xref py py-class docutils literal notranslate">Statistic</code></a> class.
<dl class="py attribute">
<dt class="sig sig-object py" id="tracemalloc.StatisticDiff.count">
count<a class="headerlink" href="#tracemalloc.StatisticDiff.count" title="Permalink to this definition">¶</a></dt>
<dd>Number of memory blocks in the new snapshot (<code class="docutils literal notranslate">int</code>): <code class="docutils literal notranslate">0</code> if
the memory blocks have been released in the new snapshot.
</dd></dl>

<dl class="py attribute">
<dt class="sig sig-object py" id="tracemalloc.StatisticDiff.count_diff">
count_diff<a class="headerlink" href="#tracemalloc.StatisticDiff.count_diff" title="Permalink to this definition">¶</a></dt>
<dd>Difference of number of memory blocks between the old and the new
snapshots (<code class="docutils literal notranslate">int</code>): <code class="docutils literal notranslate">0</code> if the memory blocks have been allocated in
the new snapshot.
</dd></dl>

<dl class="py attribute">
<dt class="sig sig-object py" id="tracemalloc.StatisticDiff.size">
size<a class="headerlink" href="#tracemalloc.StatisticDiff.size" title="Permalink to this definition">¶</a></dt>
<dd>Total size of memory blocks in bytes in the new snapshot (<code class="docutils literal notranslate">int</code>):
<code class="docutils literal notranslate">0</code> if the memory blocks have been released in the new snapshot.
</dd></dl>

<dl class="py attribute">
<dt class="sig sig-object py" id="tracemalloc.StatisticDiff.size_diff">
size_diff<a class="headerlink" href="#tracemalloc.StatisticDiff.size_diff" title="Permalink to this definition">¶</a></dt>
<dd>Difference of total size of memory blocks in bytes between the old and
the new snapshots (<code class="docutils literal notranslate">int</code>): <code class="docutils literal notranslate">0</code> if the memory blocks have been
allocated in the new snapshot.
</dd></dl>

<dl class="py attribute">
<dt class="sig sig-object py" id="tracemalloc.StatisticDiff.traceback">
traceback<a class="headerlink" href="#tracemalloc.StatisticDiff.traceback" title="Permalink to this definition">¶</a></dt>
<dd>Traceback where the memory blocks were allocated, <a class="reference internal" href="#tracemalloc.Traceback" title="tracemalloc.Traceback"><code class="xref py py-class docutils literal notranslate">Traceback</code></a>
instance.
</dd></dl>

</dd></dl>

</section>
<section id="trace">
<h3>Trace<a class="headerlink" href="#trace" title="Permalink to this headline">¶</a></h3>
<dl class="py class">
<dt class="sig sig-object py" id="tracemalloc.Trace">
class tracemalloc.Trace<a class="headerlink" href="#tracemalloc.Trace" title="Permalink to this definition">¶</a></dt>
<dd>Trace of a memory block.
The <a class="reference internal" href="#tracemalloc.Snapshot.traces" title="tracemalloc.Snapshot.traces"><code class="xref py py-attr docutils literal notranslate">Snapshot.traces</code></a> attribute is a sequence of <a class="reference internal" href="#tracemalloc.Trace" title="tracemalloc.Trace"><code class="xref py py-class docutils literal notranslate">Trace</code></a>
instances.
<div class="versionchanged">
Changed in version 3.6: Added the <a class="reference internal" href="#tracemalloc.Trace.domain" title="tracemalloc.Trace.domain"><code class="xref py py-attr docutils literal notranslate">domain</code></a> attribute.
</div>
<dl class="py attribute">
<dt class="sig sig-object py" id="tracemalloc.Trace.domain">
domain<a class="headerlink" href="#tracemalloc.Trace.domain" title="Permalink to this definition">¶</a></dt>
<dd>Address space of a memory block (<code class="docutils literal notranslate">int</code>). Read-only property.
tracemalloc uses the domain <code class="docutils literal notranslate">0</code> to trace memory allocations made by
Python. C extensions can use other domains to trace other resources.
</dd></dl>

<dl class="py attribute">
<dt class="sig sig-object py" id="tracemalloc.Trace.size">
size<a class="headerlink" href="#tracemalloc.Trace.size" title="Permalink to this definition">¶</a></dt>
<dd>Size of the memory block in bytes (<code class="docutils literal notranslate">int</code>).
</dd></dl>

<dl class="py attribute">
<dt class="sig sig-object py" id="tracemalloc.Trace.traceback">
traceback<a class="headerlink" href="#tracemalloc.Trace.traceback" title="Permalink to this definition">¶</a></dt>
<dd>Traceback where the memory block was allocated, <a class="reference internal" href="#tracemalloc.Traceback" title="tracemalloc.Traceback"><code class="xref py py-class docutils literal notranslate">Traceback</code></a>
instance.
</dd></dl>

</dd></dl>

</section>
<section id="traceback">
<h3>Traceback<a class="headerlink" href="#traceback" title="Permalink to this headline">¶</a></h3>
<dl class="py class">
<dt class="sig sig-object py" id="tracemalloc.Traceback">
class tracemalloc.Traceback<a class="headerlink" href="#tracemalloc.Traceback" title="Permalink to this definition">¶</a></dt>
<dd>Sequence of <a class="reference internal" href="#tracemalloc.Frame" title="tracemalloc.Frame"><code class="xref py py-class docutils literal notranslate">Frame</code></a> instances sorted from the oldest frame to the
most recent frame.
A traceback contains at least <code class="docutils literal notranslate">1</code> frame. If the <code class="docutils literal notranslate">tracemalloc</code> module
failed to get a frame, the filename <code class="docutils literal notranslate">&quot;&lt;unknown&gt;&quot;</code> at line number <code class="docutils literal notranslate">0</code> is
used.
When a snapshot is taken, tracebacks of traces are limited to
<a class="reference internal" href="#tracemalloc.get_traceback_limit" title="tracemalloc.get_traceback_limit"><code class="xref py py-func docutils literal notranslate">get_traceback_limit()</code></a> frames. See the <a class="reference internal" href="#tracemalloc.take_snapshot" title="tracemalloc.take_snapshot"><code class="xref py py-func docutils literal notranslate">take_snapshot()</code></a> function.
The original number of frames of the traceback is stored in the
<a class="reference internal" href="#tracemalloc.Traceback.total_nframe" title="tracemalloc.Traceback.total_nframe"><code class="xref py py-attr docutils literal notranslate">Traceback.total_nframe</code></a> attribute. That allows to know if a traceback
has been truncated by the traceback limit.
The <a class="reference internal" href="#tracemalloc.Trace.traceback" title="tracemalloc.Trace.traceback"><code class="xref py py-attr docutils literal notranslate">Trace.traceback</code></a> attribute is an instance of <a class="reference internal" href="#tracemalloc.Traceback" title="tracemalloc.Traceback"><code class="xref py py-class docutils literal notranslate">Traceback</code></a>
instance.
<div class="versionchanged">
Changed in version 3.7: Frames are now sorted from the oldest to the most recent, instead of most recent to oldest.
</div>
<dl class="py attribute">
<dt class="sig sig-object py" id="tracemalloc.Traceback.total_nframe">
total_nframe<a class="headerlink" href="#tracemalloc.Traceback.total_nframe" title="Permalink to this definition">¶</a></dt>
<dd>Total number of frames that composed the traceback before truncation.
This attribute can be set to <code class="docutils literal notranslate">None</code> if the information is not
available.
</dd></dl>

<div class="versionchanged">
Changed in version 3.9: The <a class="reference internal" href="#tracemalloc.Traceback.total_nframe" title="tracemalloc.Traceback.total_nframe"><code class="xref py py-attr docutils literal notranslate">Traceback.total_nframe</code></a> attribute was added.
</div>
<dl class="py method">
<dt class="sig sig-object py" id="tracemalloc.Traceback.format">
format(limit=None, most_recent_first=False)<a class="headerlink" href="#tracemalloc.Traceback.format" title="Permalink to this definition">¶</a></dt>
<dd>Format the traceback as a list of lines. Use the <a class="reference internal" href="linecache.html#module-linecache" title="linecache: Provides random access to individual lines from text files."><code class="xref py py-mod docutils literal notranslate">linecache</code></a> 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
<code class="docutils literal notranslate">abs(limit)</code> oldest frames. If most_recent_first is <code class="docutils literal notranslate">True</code>, the order
of the formatted frames is reversed, returning the most recent frame first
instead of last.
Similar to the <a class="reference internal" href="traceback.html#traceback.format_tb" title="traceback.format_tb"><code class="xref py py-func docutils literal notranslate">traceback.format_tb()</code></a> function, except that
<a class="reference internal" href="#tracemalloc.Traceback.format" title="tracemalloc.Traceback.format"><code class="xref py py-meth docutils literal notranslate">format()</code></a> does not include newlines.
Example:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>print(&quot;Traceback (most recent call first):&quot;)
for line in traceback:
 print(line)
</pre></div>
</div>
Output:
<div class="highlight-python3 notranslate"><div class="highlight"><pre>Traceback (most recent call first):
 File &quot;test.py&quot;, line 9
 obj = Object()
 File &quot;test.py&quot;, line 12
 tb = tracemalloc.get_object_traceback(f())
</pre></div>
</div>
</dd></dl>

</dd></dl>

</section>
</section>
</section>

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 <h3><a href="../contents.html">Table of Contents</a></h3>
 <ul>
<li><a class="reference internal" href="#"><code class="xref py py-mod docutils literal notranslate">tracemalloc</code> — Trace memory allocations</a><ul>
<li><a class="reference internal" href="#examples">Examples</a><ul>
<li><a class="reference internal" href="#display-the-top-10">Display the top 10</a></li>
<li><a class="reference internal" href="#compute-differences">Compute differences</a></li>
<li><a class="reference internal" href="#get-the-traceback-of-a-memory-block">Get the traceback of a memory block</a></li>
<li><a class="reference internal" href="#pretty-top">Pretty top</a><ul>
<li><a class="reference internal" href="#record-the-current-and-peak-size-of-all-traced-memory-blocks">Record the current and peak size of all traced memory blocks</a></li>
</ul>
</li>
</ul>
</li>
<li><a class="reference internal" href="#api">API</a><ul>
<li><a class="reference internal" href="#functions">Functions</a></li>
<li><a class="reference internal" href="#domainfilter">DomainFilter</a></li>
<li><a class="reference internal" href="#filter">Filter</a></li>
<li><a class="reference internal" href="#frame">Frame</a></li>
<li><a class="reference internal" href="#snapshot">Snapshot</a></li>
<li><a class="reference internal" href="#statistic">Statistic</a></li>
<li><a class="reference internal" href="#statisticdiff">StatisticDiff</a></li>
<li><a class="reference internal" href="#trace">Trace</a></li>
<li><a class="reference internal" href="#traceback">Traceback</a></li>
</ul>
</li>
</ul>
</li>
</ul>

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