|
|
|
|
|
<!DOCTYPE html>
|
|
|
|
|
|
<html xmlns="http://www.w3.org/1999/xhtml">
|
|
|
<head>
|
|
|
<meta charset="utf-8" />
|
|
|
<title>Instrumenting CPython with DTrace and SystemTap — Python 3.7.4 documentation</title>
|
|
|
<link rel="stylesheet" href="../_static/pydoctheme.css" type="text/css" />
|
|
|
<link rel="stylesheet" href="../_static/pygments.css" type="text/css" />
|
|
|
|
|
|
<script type="text/javascript" id="documentation_options" data-url_root="../" src="../_static/documentation_options.js"></script>
|
|
|
<script type="text/javascript" src="../_static/jquery.js"></script>
|
|
|
<script type="text/javascript" src="../_static/underscore.js"></script>
|
|
|
<script type="text/javascript" src="../_static/doctools.js"></script>
|
|
|
<script type="text/javascript" src="../_static/language_data.js"></script>
|
|
|
|
|
|
<script type="text/javascript" src="../_static/sidebar.js"></script>
|
|
|
|
|
|
<link rel="search" type="application/opensearchdescription+xml"
|
|
|
title="Search within Python 3.7.4 documentation"
|
|
|
href="../_static/opensearch.xml"/>
|
|
|
<link rel="author" title="About these documents" href="../about.html" />
|
|
|
<link rel="index" title="Index" href="../genindex.html" />
|
|
|
<link rel="search" title="Search" href="../search.html" />
|
|
|
<link rel="copyright" title="Copyright" href="../copyright.html" />
|
|
|
<link rel="next" title="Python Frequently Asked Questions" href="../faq/index.html" />
|
|
|
<link rel="prev" title="Argument Clinic How-To" href="clinic.html" />
|
|
|
<link rel="shortcut icon" type="image/png" href="../_static/py.png" />
|
|
|
<link rel="canonical" href="https://docs.python.org/3/howto/instrumentation.html" />
|
|
|
|
|
|
<script type="text/javascript" src="../_static/copybutton.js"></script>
|
|
|
<script type="text/javascript" src="../_static/switchers.js"></script>
|
|
|
|
|
|
|
|
|
|
|
|
<style>
|
|
|
@media only screen {
|
|
|
table.full-width-table {
|
|
|
width: 100%;
|
|
|
}
|
|
|
}
|
|
|
</style>
|
|
|
|
|
|
|
|
|
</head><body>
|
|
|
|
|
|
<div class="related" role="navigation" aria-label="related navigation">
|
|
|
<h3>Navigation</h3>
|
|
|
<ul>
|
|
|
<li class="right" style="margin-right: 10px">
|
|
|
<a href="../genindex.html" title="General Index"
|
|
|
accesskey="I">index</a></li>
|
|
|
<li class="right" >
|
|
|
<a href="../py-modindex.html" title="Python Module Index"
|
|
|
>modules</a> |</li>
|
|
|
<li class="right" >
|
|
|
<a href="../faq/index.html" title="Python Frequently Asked Questions"
|
|
|
accesskey="N">next</a> |</li>
|
|
|
<li class="right" >
|
|
|
<a href="clinic.html" title="Argument Clinic How-To"
|
|
|
accesskey="P">previous</a> |</li>
|
|
|
<li><img src="../_static/py.png" alt=""
|
|
|
style="vertical-align: middle; margin-top: -1px"/></li>
|
|
|
<li><a href="https://www.python.org/">Python</a> »</li>
|
|
|
<li>
|
|
|
<span class="language_switcher_placeholder">en</span>
|
|
|
<span class="version_switcher_placeholder">3.7.4</span>
|
|
|
<a href="../index.html">Documentation </a> »
|
|
|
</li>
|
|
|
|
|
|
<li class="nav-item nav-item-1"><a href="index.html" accesskey="U">Python HOWTOs</a> »</li>
|
|
|
<li class="right">
|
|
|
|
|
|
|
|
|
<div class="inline-search" style="display: none" role="search">
|
|
|
<form class="inline-search" action="../search.html" method="get">
|
|
|
<input placeholder="Quick search" type="text" name="q" />
|
|
|
<input type="submit" value="Go" />
|
|
|
<input type="hidden" name="check_keywords" value="yes" />
|
|
|
<input type="hidden" name="area" value="default" />
|
|
|
</form>
|
|
|
</div>
|
|
|
<script type="text/javascript">$('.inline-search').show(0);</script>
|
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
</div>
|
|
|
|
|
|
<div class="document">
|
|
|
<div class="documentwrapper">
|
|
|
<div class="bodywrapper">
|
|
|
<div class="body" role="main">
|
|
|
|
|
|
<div class="section" id="instrumenting-cpython-with-dtrace-and-systemtap">
|
|
|
<span id="instrumentation"></span><h1>Instrumenting CPython with DTrace and SystemTap<a class="headerlink" href="#instrumenting-cpython-with-dtrace-and-systemtap" title="Permalink to this headline">¶</a></h1>
|
|
|
<dl class="field-list simple">
|
|
|
<dt class="field-odd">author</dt>
|
|
|
<dd class="field-odd"><p>David Malcolm</p>
|
|
|
</dd>
|
|
|
<dt class="field-even">author</dt>
|
|
|
<dd class="field-even"><p>Łukasz Langa</p>
|
|
|
</dd>
|
|
|
</dl>
|
|
|
<p>DTrace and SystemTap are monitoring tools, each providing a way to inspect
|
|
|
what the processes on a computer system are doing. They both use
|
|
|
domain-specific languages allowing a user to write scripts which:</p>
|
|
|
<blockquote>
|
|
|
<div><ul class="simple">
|
|
|
<li><p>filter which processes are to be observed</p></li>
|
|
|
<li><p>gather data from the processes of interest</p></li>
|
|
|
<li><p>generate reports on the data</p></li>
|
|
|
</ul>
|
|
|
</div></blockquote>
|
|
|
<p>As of Python 3.6, CPython can be built with embedded “markers”, also
|
|
|
known as “probes”, that can be observed by a DTrace or SystemTap script,
|
|
|
making it easier to monitor what the CPython processes on a system are
|
|
|
doing.</p>
|
|
|
<div class="impl-detail compound">
|
|
|
<p><strong>CPython implementation detail:</strong> DTrace markers are implementation details of the CPython interpreter.
|
|
|
No guarantees are made about probe compatibility between versions of
|
|
|
CPython. DTrace scripts can stop working or work incorrectly without
|
|
|
warning when changing CPython versions.</p>
|
|
|
</div>
|
|
|
<div class="section" id="enabling-the-static-markers">
|
|
|
<h2>Enabling the static markers<a class="headerlink" href="#enabling-the-static-markers" title="Permalink to this headline">¶</a></h2>
|
|
|
<p>macOS comes with built-in support for DTrace. On Linux, in order to
|
|
|
build CPython with the embedded markers for SystemTap, the SystemTap
|
|
|
development tools must be installed.</p>
|
|
|
<p>On a Linux machine, this can be done via:</p>
|
|
|
<div class="highlight-shell-session notranslate"><div class="highlight"><pre><span></span><span class="gp">$</span> yum install systemtap-sdt-devel
|
|
|
</pre></div>
|
|
|
</div>
|
|
|
<p>or:</p>
|
|
|
<div class="highlight-shell-session notranslate"><div class="highlight"><pre><span></span><span class="gp">$</span> sudo apt-get install systemtap-sdt-dev
|
|
|
</pre></div>
|
|
|
</div>
|
|
|
<p>CPython must then be configured <code class="docutils literal notranslate"><span class="pre">--with-dtrace</span></code>:</p>
|
|
|
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>checking for --with-dtrace... yes
|
|
|
</pre></div>
|
|
|
</div>
|
|
|
<p>On macOS, you can list available DTrace probes by running a Python
|
|
|
process in the background and listing all probes made available by the
|
|
|
Python provider:</p>
|
|
|
<div class="highlight-shell-session notranslate"><div class="highlight"><pre><span></span><span class="gp">$</span> python3.6 -q <span class="p">&</span>
|
|
|
<span class="gp">$</span> sudo dtrace -l -P python<span class="nv">$!</span> <span class="c1"># or: dtrace -l -m python3.6</span>
|
|
|
|
|
|
<span class="go"> ID PROVIDER MODULE FUNCTION NAME</span>
|
|
|
<span class="go">29564 python18035 python3.6 _PyEval_EvalFrameDefault function-entry</span>
|
|
|
<span class="go">29565 python18035 python3.6 dtrace_function_entry function-entry</span>
|
|
|
<span class="go">29566 python18035 python3.6 _PyEval_EvalFrameDefault function-return</span>
|
|
|
<span class="go">29567 python18035 python3.6 dtrace_function_return function-return</span>
|
|
|
<span class="go">29568 python18035 python3.6 collect gc-done</span>
|
|
|
<span class="go">29569 python18035 python3.6 collect gc-start</span>
|
|
|
<span class="go">29570 python18035 python3.6 _PyEval_EvalFrameDefault line</span>
|
|
|
<span class="go">29571 python18035 python3.6 maybe_dtrace_line line</span>
|
|
|
</pre></div>
|
|
|
</div>
|
|
|
<p>On Linux, you can verify if the SystemTap static markers are present in
|
|
|
the built binary by seeing if it contains a “.note.stapsdt” section.</p>
|
|
|
<div class="highlight-shell-session notranslate"><div class="highlight"><pre><span></span><span class="gp">$</span> readelf -S ./python <span class="p">|</span> grep .note.stapsdt
|
|
|
<span class="go">[30] .note.stapsdt NOTE 0000000000000000 00308d78</span>
|
|
|
</pre></div>
|
|
|
</div>
|
|
|
<p>If you’ve built Python as a shared library (with –enable-shared), you
|
|
|
need to look instead within the shared library. For example:</p>
|
|
|
<div class="highlight-shell-session notranslate"><div class="highlight"><pre><span></span><span class="gp">$</span> readelf -S libpython3.3dm.so.1.0 <span class="p">|</span> grep .note.stapsdt
|
|
|
<span class="go">[29] .note.stapsdt NOTE 0000000000000000 00365b68</span>
|
|
|
</pre></div>
|
|
|
</div>
|
|
|
<p>Sufficiently modern readelf can print the metadata:</p>
|
|
|
<div class="highlight-shell-session notranslate"><div class="highlight"><pre><span></span><span class="gp">$</span> readelf -n ./python
|
|
|
|
|
|
<span class="go">Displaying notes found at file offset 0x00000254 with length 0x00000020:</span>
|
|
|
<span class="go"> Owner Data size Description</span>
|
|
|
<span class="go"> GNU 0x00000010 NT_GNU_ABI_TAG (ABI version tag)</span>
|
|
|
<span class="go"> OS: Linux, ABI: 2.6.32</span>
|
|
|
|
|
|
<span class="go">Displaying notes found at file offset 0x00000274 with length 0x00000024:</span>
|
|
|
<span class="go"> Owner Data size Description</span>
|
|
|
<span class="go"> GNU 0x00000014 NT_GNU_BUILD_ID (unique build ID bitstring)</span>
|
|
|
<span class="go"> Build ID: df924a2b08a7e89f6e11251d4602022977af2670</span>
|
|
|
|
|
|
<span class="go">Displaying notes found at file offset 0x002d6c30 with length 0x00000144:</span>
|
|
|
<span class="go"> Owner Data size Description</span>
|
|
|
<span class="go"> stapsdt 0x00000031 NT_STAPSDT (SystemTap probe descriptors)</span>
|
|
|
<span class="go"> Provider: python</span>
|
|
|
<span class="go"> Name: gc__start</span>
|
|
|
<span class="go"> Location: 0x00000000004371c3, Base: 0x0000000000630ce2, Semaphore: 0x00000000008d6bf6</span>
|
|
|
<span class="go"> Arguments: -4@%ebx</span>
|
|
|
<span class="go"> stapsdt 0x00000030 NT_STAPSDT (SystemTap probe descriptors)</span>
|
|
|
<span class="go"> Provider: python</span>
|
|
|
<span class="go"> Name: gc__done</span>
|
|
|
<span class="go"> Location: 0x00000000004374e1, Base: 0x0000000000630ce2, Semaphore: 0x00000000008d6bf8</span>
|
|
|
<span class="go"> Arguments: -8@%rax</span>
|
|
|
<span class="go"> stapsdt 0x00000045 NT_STAPSDT (SystemTap probe descriptors)</span>
|
|
|
<span class="go"> Provider: python</span>
|
|
|
<span class="go"> Name: function__entry</span>
|
|
|
<span class="go"> Location: 0x000000000053db6c, Base: 0x0000000000630ce2, Semaphore: 0x00000000008d6be8</span>
|
|
|
<span class="go"> Arguments: 8@%rbp 8@%r12 -4@%eax</span>
|
|
|
<span class="go"> stapsdt 0x00000046 NT_STAPSDT (SystemTap probe descriptors)</span>
|
|
|
<span class="go"> Provider: python</span>
|
|
|
<span class="go"> Name: function__return</span>
|
|
|
<span class="go"> Location: 0x000000000053dba8, Base: 0x0000000000630ce2, Semaphore: 0x00000000008d6bea</span>
|
|
|
<span class="go"> Arguments: 8@%rbp 8@%r12 -4@%eax</span>
|
|
|
</pre></div>
|
|
|
</div>
|
|
|
<p>The above metadata contains information for SystemTap describing how it
|
|
|
can patch strategically-placed machine code instructions to enable the
|
|
|
tracing hooks used by a SystemTap script.</p>
|
|
|
</div>
|
|
|
<div class="section" id="static-dtrace-probes">
|
|
|
<h2>Static DTrace probes<a class="headerlink" href="#static-dtrace-probes" title="Permalink to this headline">¶</a></h2>
|
|
|
<p>The following example DTrace script can be used to show the call/return
|
|
|
hierarchy of a Python script, only tracing within the invocation of
|
|
|
a function called “start”. In other words, import-time function
|
|
|
invocations are not going to be listed:</p>
|
|
|
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>self int indent;
|
|
|
|
|
|
python$target:::function-entry
|
|
|
/copyinstr(arg1) == "start"/
|
|
|
{
|
|
|
self->trace = 1;
|
|
|
}
|
|
|
|
|
|
python$target:::function-entry
|
|
|
/self->trace/
|
|
|
{
|
|
|
printf("%d\t%*s:", timestamp, 15, probename);
|
|
|
printf("%*s", self->indent, "");
|
|
|
printf("%s:%s:%d\n", basename(copyinstr(arg0)), copyinstr(arg1), arg2);
|
|
|
self->indent++;
|
|
|
}
|
|
|
|
|
|
python$target:::function-return
|
|
|
/self->trace/
|
|
|
{
|
|
|
self->indent--;
|
|
|
printf("%d\t%*s:", timestamp, 15, probename);
|
|
|
printf("%*s", self->indent, "");
|
|
|
printf("%s:%s:%d\n", basename(copyinstr(arg0)), copyinstr(arg1), arg2);
|
|
|
}
|
|
|
|
|
|
python$target:::function-return
|
|
|
/copyinstr(arg1) == "start"/
|
|
|
{
|
|
|
self->trace = 0;
|
|
|
}
|
|
|
</pre></div>
|
|
|
</div>
|
|
|
<p>It can be invoked like this:</p>
|
|
|
<div class="highlight-shell-session notranslate"><div class="highlight"><pre><span></span><span class="gp">$</span> sudo dtrace -q -s call_stack.d -c <span class="s2">"python3.6 script.py"</span>
|
|
|
</pre></div>
|
|
|
</div>
|
|
|
<p>The output looks like this:</p>
|
|
|
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>156641360502280 function-entry:call_stack.py:start:23
|
|
|
156641360518804 function-entry: call_stack.py:function_1:1
|
|
|
156641360532797 function-entry: call_stack.py:function_3:9
|
|
|
156641360546807 function-return: call_stack.py:function_3:10
|
|
|
156641360563367 function-return: call_stack.py:function_1:2
|
|
|
156641360578365 function-entry: call_stack.py:function_2:5
|
|
|
156641360591757 function-entry: call_stack.py:function_1:1
|
|
|
156641360605556 function-entry: call_stack.py:function_3:9
|
|
|
156641360617482 function-return: call_stack.py:function_3:10
|
|
|
156641360629814 function-return: call_stack.py:function_1:2
|
|
|
156641360642285 function-return: call_stack.py:function_2:6
|
|
|
156641360656770 function-entry: call_stack.py:function_3:9
|
|
|
156641360669707 function-return: call_stack.py:function_3:10
|
|
|
156641360687853 function-entry: call_stack.py:function_4:13
|
|
|
156641360700719 function-return: call_stack.py:function_4:14
|
|
|
156641360719640 function-entry: call_stack.py:function_5:18
|
|
|
156641360732567 function-return: call_stack.py:function_5:21
|
|
|
156641360747370 function-return:call_stack.py:start:28
|
|
|
</pre></div>
|
|
|
</div>
|
|
|
</div>
|
|
|
<div class="section" id="static-systemtap-markers">
|
|
|
<h2>Static SystemTap markers<a class="headerlink" href="#static-systemtap-markers" title="Permalink to this headline">¶</a></h2>
|
|
|
<p>The low-level way to use the SystemTap integration is to use the static
|
|
|
markers directly. This requires you to explicitly state the binary file
|
|
|
containing them.</p>
|
|
|
<p>For example, this SystemTap script can be used to show the call/return
|
|
|
hierarchy of a Python script:</p>
|
|
|
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>probe process("python").mark("function__entry") {
|
|
|
filename = user_string($arg1);
|
|
|
funcname = user_string($arg2);
|
|
|
lineno = $arg3;
|
|
|
|
|
|
printf("%s => %s in %s:%d\\n",
|
|
|
thread_indent(1), funcname, filename, lineno);
|
|
|
}
|
|
|
|
|
|
probe process("python").mark("function__return") {
|
|
|
filename = user_string($arg1);
|
|
|
funcname = user_string($arg2);
|
|
|
lineno = $arg3;
|
|
|
|
|
|
printf("%s <= %s in %s:%d\\n",
|
|
|
thread_indent(-1), funcname, filename, lineno);
|
|
|
}
|
|
|
</pre></div>
|
|
|
</div>
|
|
|
<p>It can be invoked like this:</p>
|
|
|
<div class="highlight-shell-session notranslate"><div class="highlight"><pre><span></span><span class="gp">$</span> stap <span class="se">\</span>
|
|
|
show-call-hierarchy.stp <span class="se">\</span>
|
|
|
-c <span class="s2">"./python test.py"</span>
|
|
|
</pre></div>
|
|
|
</div>
|
|
|
<p>The output looks like this:</p>
|
|
|
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>11408 python(8274): => __contains__ in Lib/_abcoll.py:362
|
|
|
11414 python(8274): => __getitem__ in Lib/os.py:425
|
|
|
11418 python(8274): => encode in Lib/os.py:490
|
|
|
11424 python(8274): <= encode in Lib/os.py:493
|
|
|
11428 python(8274): <= __getitem__ in Lib/os.py:426
|
|
|
11433 python(8274): <= __contains__ in Lib/_abcoll.py:366
|
|
|
</pre></div>
|
|
|
</div>
|
|
|
<p>where the columns are:</p>
|
|
|
<blockquote>
|
|
|
<div><ul class="simple">
|
|
|
<li><p>time in microseconds since start of script</p></li>
|
|
|
<li><p>name of executable</p></li>
|
|
|
<li><p>PID of process</p></li>
|
|
|
</ul>
|
|
|
</div></blockquote>
|
|
|
<p>and the remainder indicates the call/return hierarchy as the script executes.</p>
|
|
|
<p>For a <cite>–enable-shared</cite> build of CPython, the markers are contained within the
|
|
|
libpython shared library, and the probe’s dotted path needs to reflect this. For
|
|
|
example, this line from the above example:</p>
|
|
|
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>probe process("python").mark("function__entry") {
|
|
|
</pre></div>
|
|
|
</div>
|
|
|
<p>should instead read:</p>
|
|
|
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>probe process("python").library("libpython3.6dm.so.1.0").mark("function__entry") {
|
|
|
</pre></div>
|
|
|
</div>
|
|
|
<p>(assuming a debug build of CPython 3.6)</p>
|
|
|
</div>
|
|
|
<div class="section" id="available-static-markers">
|
|
|
<h2>Available static markers<a class="headerlink" href="#available-static-markers" title="Permalink to this headline">¶</a></h2>
|
|
|
<dl class="function">
|
|
|
<dt id="c.function__entry">
|
|
|
<code class="descname">function__entry</code><span class="sig-paren">(</span>str<em> filename</em>, str<em> funcname</em>, int<em> lineno</em><span class="sig-paren">)</span><a class="headerlink" href="#c.function__entry" title="Permalink to this definition">¶</a></dt>
|
|
|
<dd><p>This marker indicates that execution of a Python function has begun.
|
|
|
It is only triggered for pure-Python (bytecode) functions.</p>
|
|
|
<p>The filename, function name, and line number are provided back to the
|
|
|
tracing script as positional arguments, which must be accessed using
|
|
|
<code class="docutils literal notranslate"><span class="pre">$arg1</span></code>, <code class="docutils literal notranslate"><span class="pre">$arg2</span></code>, <code class="docutils literal notranslate"><span class="pre">$arg3</span></code>:</p>
|
|
|
<blockquote>
|
|
|
<div><ul class="simple">
|
|
|
<li><p><code class="docutils literal notranslate"><span class="pre">$arg1</span></code> : <code class="docutils literal notranslate"><span class="pre">(const</span> <span class="pre">char</span> <span class="pre">*)</span></code> filename, accessible using <code class="docutils literal notranslate"><span class="pre">user_string($arg1)</span></code></p></li>
|
|
|
<li><p><code class="docutils literal notranslate"><span class="pre">$arg2</span></code> : <code class="docutils literal notranslate"><span class="pre">(const</span> <span class="pre">char</span> <span class="pre">*)</span></code> function name, accessible using
|
|
|
<code class="docutils literal notranslate"><span class="pre">user_string($arg2)</span></code></p></li>
|
|
|
<li><p><code class="docutils literal notranslate"><span class="pre">$arg3</span></code> : <code class="docutils literal notranslate"><span class="pre">int</span></code> line number</p></li>
|
|
|
</ul>
|
|
|
</div></blockquote>
|
|
|
</dd></dl>
|
|
|
|
|
|
<dl class="function">
|
|
|
<dt id="c.function__return">
|
|
|
<code class="descname">function__return</code><span class="sig-paren">(</span>str<em> filename</em>, str<em> funcname</em>, int<em> lineno</em><span class="sig-paren">)</span><a class="headerlink" href="#c.function__return" title="Permalink to this definition">¶</a></dt>
|
|
|
<dd><p>This marker is the converse of <a class="reference internal" href="#c.function__entry" title="function__entry"><code class="xref c c-func docutils literal notranslate"><span class="pre">function__entry()</span></code></a>, and indicates that
|
|
|
execution of a Python function has ended (either via <code class="docutils literal notranslate"><span class="pre">return</span></code>, or via an
|
|
|
exception). It is only triggered for pure-Python (bytecode) functions.</p>
|
|
|
<p>The arguments are the same as for <a class="reference internal" href="#c.function__entry" title="function__entry"><code class="xref c c-func docutils literal notranslate"><span class="pre">function__entry()</span></code></a></p>
|
|
|
</dd></dl>
|
|
|
|
|
|
<dl class="function">
|
|
|
<dt id="c.line">
|
|
|
<code class="descname">line</code><span class="sig-paren">(</span>str<em> filename</em>, str<em> funcname</em>, int<em> lineno</em><span class="sig-paren">)</span><a class="headerlink" href="#c.line" title="Permalink to this definition">¶</a></dt>
|
|
|
<dd><p>This marker indicates a Python line is about to be executed. It is
|
|
|
the equivalent of line-by-line tracing with a Python profiler. It is
|
|
|
not triggered within C functions.</p>
|
|
|
<p>The arguments are the same as for <a class="reference internal" href="#c.function__entry" title="function__entry"><code class="xref c c-func docutils literal notranslate"><span class="pre">function__entry()</span></code></a>.</p>
|
|
|
</dd></dl>
|
|
|
|
|
|
<dl class="function">
|
|
|
<dt id="c.gc__start">
|
|
|
<code class="descname">gc__start</code><span class="sig-paren">(</span>int<em> generation</em><span class="sig-paren">)</span><a class="headerlink" href="#c.gc__start" title="Permalink to this definition">¶</a></dt>
|
|
|
<dd><p>Fires when the Python interpreter starts a garbage collection cycle.
|
|
|
<code class="docutils literal notranslate"><span class="pre">arg0</span></code> is the generation to scan, like <a class="reference internal" href="../library/gc.html#gc.collect" title="gc.collect"><code class="xref py py-func docutils literal notranslate"><span class="pre">gc.collect()</span></code></a>.</p>
|
|
|
</dd></dl>
|
|
|
|
|
|
<dl class="function">
|
|
|
<dt id="c.gc__done">
|
|
|
<code class="descname">gc__done</code><span class="sig-paren">(</span>long<em> collected</em><span class="sig-paren">)</span><a class="headerlink" href="#c.gc__done" title="Permalink to this definition">¶</a></dt>
|
|
|
<dd><p>Fires when the Python interpreter finishes a garbage collection
|
|
|
cycle. <code class="docutils literal notranslate"><span class="pre">arg0</span></code> is the number of collected objects.</p>
|
|
|
</dd></dl>
|
|
|
|
|
|
<dl class="function">
|
|
|
<dt id="c.import__find__load__start">
|
|
|
<code class="descname">import__find__load__start</code><span class="sig-paren">(</span>str<em> modulename</em><span class="sig-paren">)</span><a class="headerlink" href="#c.import__find__load__start" title="Permalink to this definition">¶</a></dt>
|
|
|
<dd><p>Fires before <a class="reference internal" href="../library/importlib.html#module-importlib" title="importlib: The implementation of the import machinery."><code class="xref py py-mod docutils literal notranslate"><span class="pre">importlib</span></code></a> attempts to find and load the module.
|
|
|
<code class="docutils literal notranslate"><span class="pre">arg0</span></code> is the module name.</p>
|
|
|
<div class="versionadded">
|
|
|
<p><span class="versionmodified added">New in version 3.7.</span></p>
|
|
|
</div>
|
|
|
</dd></dl>
|
|
|
|
|
|
<dl class="function">
|
|
|
<dt id="c.import__find__load__done">
|
|
|
<code class="descname">import__find__load__done</code><span class="sig-paren">(</span>str<em> modulename</em>, int<em> found</em><span class="sig-paren">)</span><a class="headerlink" href="#c.import__find__load__done" title="Permalink to this definition">¶</a></dt>
|
|
|
<dd><p>Fires after <a class="reference internal" href="../library/importlib.html#module-importlib" title="importlib: The implementation of the import machinery."><code class="xref py py-mod docutils literal notranslate"><span class="pre">importlib</span></code></a>’s find_and_load function is called.
|
|
|
<code class="docutils literal notranslate"><span class="pre">arg0</span></code> is the module name, <code class="docutils literal notranslate"><span class="pre">arg1</span></code> indicates if module was
|
|
|
successfully loaded.</p>
|
|
|
<div class="versionadded">
|
|
|
<p><span class="versionmodified added">New in version 3.7.</span></p>
|
|
|
</div>
|
|
|
</dd></dl>
|
|
|
|
|
|
</div>
|
|
|
<div class="section" id="systemtap-tapsets">
|
|
|
<h2>SystemTap Tapsets<a class="headerlink" href="#systemtap-tapsets" title="Permalink to this headline">¶</a></h2>
|
|
|
<p>The higher-level way to use the SystemTap integration is to use a “tapset”:
|
|
|
SystemTap’s equivalent of a library, which hides some of the lower-level
|
|
|
details of the static markers.</p>
|
|
|
<p>Here is a tapset file, based on a non-shared build of CPython:</p>
|
|
|
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>/*
|
|
|
Provide a higher-level wrapping around the function__entry and
|
|
|
function__return markers:
|
|
|
\*/
|
|
|
probe python.function.entry = process("python").mark("function__entry")
|
|
|
{
|
|
|
filename = user_string($arg1);
|
|
|
funcname = user_string($arg2);
|
|
|
lineno = $arg3;
|
|
|
frameptr = $arg4
|
|
|
}
|
|
|
probe python.function.return = process("python").mark("function__return")
|
|
|
{
|
|
|
filename = user_string($arg1);
|
|
|
funcname = user_string($arg2);
|
|
|
lineno = $arg3;
|
|
|
frameptr = $arg4
|
|
|
}
|
|
|
</pre></div>
|
|
|
</div>
|
|
|
<p>If this file is installed in SystemTap’s tapset directory (e.g.
|
|
|
<code class="docutils literal notranslate"><span class="pre">/usr/share/systemtap/tapset</span></code>), then these additional probepoints become
|
|
|
available:</p>
|
|
|
<dl class="function">
|
|
|
<dt id="c.python.function.entry">
|
|
|
<code class="descname">python.function.entry</code><span class="sig-paren">(</span>str<em> filename</em>, str<em> funcname</em>, int<em> lineno</em>, frameptr<span class="sig-paren">)</span><a class="headerlink" href="#c.python.function.entry" title="Permalink to this definition">¶</a></dt>
|
|
|
<dd><p>This probe point indicates that execution of a Python function has begun.
|
|
|
It is only triggered for pure-Python (bytecode) functions.</p>
|
|
|
</dd></dl>
|
|
|
|
|
|
<dl class="function">
|
|
|
<dt id="c.python.function.return">
|
|
|
<code class="descname">python.function.return</code><span class="sig-paren">(</span>str<em> filename</em>, str<em> funcname</em>, int<em> lineno</em>, frameptr<span class="sig-paren">)</span><a class="headerlink" href="#c.python.function.return" title="Permalink to this definition">¶</a></dt>
|
|
|
<dd><p>This probe point is the converse of <a class="reference internal" href="#c.python.function.return" title="python.function.return"><code class="xref c c-func docutils literal notranslate"><span class="pre">python.function.return()</span></code></a>, and
|
|
|
indicates that execution of a Python function has ended (either via
|
|
|
<code class="docutils literal notranslate"><span class="pre">return</span></code>, or via an exception). It is only triggered for pure-Python
|
|
|
(bytecode) functions.</p>
|
|
|
</dd></dl>
|
|
|
|
|
|
</div>
|
|
|
<div class="section" id="examples">
|
|
|
<h2>Examples<a class="headerlink" href="#examples" title="Permalink to this headline">¶</a></h2>
|
|
|
<p>This SystemTap script uses the tapset above to more cleanly implement the
|
|
|
example given above of tracing the Python function-call hierarchy, without
|
|
|
needing to directly name the static markers:</p>
|
|
|
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>probe python.function.entry
|
|
|
{
|
|
|
printf("%s => %s in %s:%d\n",
|
|
|
thread_indent(1), funcname, filename, lineno);
|
|
|
}
|
|
|
|
|
|
probe python.function.return
|
|
|
{
|
|
|
printf("%s <= %s in %s:%d\n",
|
|
|
thread_indent(-1), funcname, filename, lineno);
|
|
|
}
|
|
|
</pre></div>
|
|
|
</div>
|
|
|
<p>The following script uses the tapset above to provide a top-like view of all
|
|
|
running CPython code, showing the top 20 most frequently-entered bytecode
|
|
|
frames, each second, across the whole system:</p>
|
|
|
<div class="highlight-none notranslate"><div class="highlight"><pre><span></span>global fn_calls;
|
|
|
|
|
|
probe python.function.entry
|
|
|
{
|
|
|
fn_calls[pid(), filename, funcname, lineno] += 1;
|
|
|
}
|
|
|
|
|
|
probe timer.ms(1000) {
|
|
|
printf("\033[2J\033[1;1H") /* clear screen \*/
|
|
|
printf("%6s %80s %6s %30s %6s\n",
|
|
|
"PID", "FILENAME", "LINE", "FUNCTION", "CALLS")
|
|
|
foreach ([pid, filename, funcname, lineno] in fn_calls- limit 20) {
|
|
|
printf("%6d %80s %6d %30s %6d\n",
|
|
|
pid, filename, lineno, funcname,
|
|
|
fn_calls[pid, filename, funcname, lineno]);
|
|
|
}
|
|
|
delete fn_calls;
|
|
|
}
|
|
|
</pre></div>
|
|
|
</div>
|
|
|
</div>
|
|
|
</div>
|
|
|
|
|
|
|
|
|
</div>
|
|
|
</div>
|
|
|
</div>
|
|
|
<div class="sphinxsidebar" role="navigation" aria-label="main navigation">
|
|
|
<div class="sphinxsidebarwrapper">
|
|
|
<h3><a href="../contents.html">Table of Contents</a></h3>
|
|
|
<ul>
|
|
|
<li><a class="reference internal" href="#">Instrumenting CPython with DTrace and SystemTap</a><ul>
|
|
|
<li><a class="reference internal" href="#enabling-the-static-markers">Enabling the static markers</a></li>
|
|
|
<li><a class="reference internal" href="#static-dtrace-probes">Static DTrace probes</a></li>
|
|
|
<li><a class="reference internal" href="#static-systemtap-markers">Static SystemTap markers</a></li>
|
|
|
<li><a class="reference internal" href="#available-static-markers">Available static markers</a></li>
|
|
|
<li><a class="reference internal" href="#systemtap-tapsets">SystemTap Tapsets</a></li>
|
|
|
<li><a class="reference internal" href="#examples">Examples</a></li>
|
|
|
</ul>
|
|
|
</li>
|
|
|
</ul>
|
|
|
|
|
|
<h4>Previous topic</h4>
|
|
|
<p class="topless"><a href="clinic.html"
|
|
|
title="previous chapter">Argument Clinic How-To</a></p>
|
|
|
<h4>Next topic</h4>
|
|
|
<p class="topless"><a href="../faq/index.html"
|
|
|
title="next chapter">Python Frequently Asked Questions</a></p>
|
|
|
<div role="note" aria-label="source link">
|
|
|
<h3>This Page</h3>
|
|
|
<ul class="this-page-menu">
|
|
|
<li><a href="../bugs.html">Report a Bug</a></li>
|
|
|
<li>
|
|
|
<a href="https://github.com/python/cpython/blob/3.7/Doc/howto/instrumentation.rst"
|
|
|
rel="nofollow">Show Source
|
|
|
</a>
|
|
|
</li>
|
|
|
</ul>
|
|
|
</div>
|
|
|
</div>
|
|
|
</div>
|
|
|
<div class="clearer"></div>
|
|
|
</div>
|
|
|
<div class="related" role="navigation" aria-label="related navigation">
|
|
|
<h3>Navigation</h3>
|
|
|
<ul>
|
|
|
<li class="right" style="margin-right: 10px">
|
|
|
<a href="../genindex.html" title="General Index"
|
|
|
>index</a></li>
|
|
|
<li class="right" >
|
|
|
<a href="../py-modindex.html" title="Python Module Index"
|
|
|
>modules</a> |</li>
|
|
|
<li class="right" >
|
|
|
<a href="../faq/index.html" title="Python Frequently Asked Questions"
|
|
|
>next</a> |</li>
|
|
|
<li class="right" >
|
|
|
<a href="clinic.html" title="Argument Clinic How-To"
|
|
|
>previous</a> |</li>
|
|
|
<li><img src="../_static/py.png" alt=""
|
|
|
style="vertical-align: middle; margin-top: -1px"/></li>
|
|
|
<li><a href="https://www.python.org/">Python</a> »</li>
|
|
|
<li>
|
|
|
<span class="language_switcher_placeholder">en</span>
|
|
|
<span class="version_switcher_placeholder">3.7.4</span>
|
|
|
<a href="../index.html">Documentation </a> »
|
|
|
</li>
|
|
|
|
|
|
<li class="nav-item nav-item-1"><a href="index.html" >Python HOWTOs</a> »</li>
|
|
|
<li class="right">
|
|
|
|
|
|
|
|
|
<div class="inline-search" style="display: none" role="search">
|
|
|
<form class="inline-search" action="../search.html" method="get">
|
|
|
<input placeholder="Quick search" type="text" name="q" />
|
|
|
<input type="submit" value="Go" />
|
|
|
<input type="hidden" name="check_keywords" value="yes" />
|
|
|
<input type="hidden" name="area" value="default" />
|
|
|
</form>
|
|
|
</div>
|
|
|
<script type="text/javascript">$('.inline-search').show(0);</script>
|
|
|
|
|
|
|
</li>
|
|
|
|
|
|
</ul>
|
|
|
</div>
|
|
|
<div class="footer">
|
|
|
© <a href="../copyright.html">Copyright</a> 2001-2019, Python Software Foundation.
|
|
|
<br />
|
|
|
The Python Software Foundation is a non-profit corporation.
|
|
|
<a href="https://www.python.org/psf/donations/">Please donate.</a>
|
|
|
<br />
|
|
|
Last updated on Jul 13, 2019.
|
|
|
<a href="../bugs.html">Found a bug</a>?
|
|
|
<br />
|
|
|
Created using <a href="http://sphinx.pocoo.org/">Sphinx</a> 2.0.1.
|
|
|
</div>
|
|
|
|
|
|
</body>
|
|
|
</html> |