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<div class="section" id="module-hotshot">
<h1>27.5. <tt class="xref docutils literal"><span class="pre">hotshot</span></tt> — High performance logging profiler<a class="headerlink" href="#module-hotshot" title="Permalink to this headline">¶</a></h1>
<p class="versionadded">
<span class="versionmodified">New in version 2.2.</span></p>
<p>This module provides a nicer interface to the <tt class="xref docutils literal"><span class="pre">_hotshot</span></tt> C module. Hotshot
is a replacement for the existing <tt class="xref docutils literal"><span class="pre">profile</span></tt> module. As it’s written mostly
in C, it should result in a much smaller performance impact than the existing
<tt class="xref docutils literal"><span class="pre">profile</span></tt> module.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">The <tt class="xref docutils literal"><span class="pre">hotshot</span></tt> module focuses on minimizing the overhead while profiling, at
the expense of long data post-processing times. For common usage it is
recommended to use <a title="Python profiler" class="reference external" href="profile.html#module-cProfile"><tt class="xref docutils literal"><span class="pre">cProfile</span></tt></a> instead. <tt class="xref docutils literal"><span class="pre">hotshot</span></tt> is not maintained and
might be removed from the standard library in the future.</p>
</div>
<p class="versionchanged">
<span class="versionmodified">Changed in version 2.5: </span>The results should be more meaningful than in the past: the timing core
contained a critical bug.</p>
<div class="admonition note">
<p class="first admonition-title">Note</p>
<p class="last">The <tt class="xref docutils literal"><span class="pre">hotshot</span></tt> profiler does not yet work well with threads. It is useful to
use an unthreaded script to run the profiler over the code you’re interested in
measuring if at all possible.</p>
</div>
<dl class="class">
<dt id="hotshot.Profile">
<em class="property">class </em><tt class="descclassname">hotshot.</tt><tt class="descname">Profile</tt><big>(</big><em>logfile</em><span class="optional">[</span>, <em>lineevents</em><span class="optional">[</span>, <em>linetimings</em><span class="optional">]</span><span class="optional">]</span><big>)</big><a class="headerlink" href="#hotshot.Profile" title="Permalink to this definition">¶</a></dt>
<dd>The profiler object. The argument <em>logfile</em> is the name of a log file to use for
logged profile data. The argument <em>lineevents</em> specifies whether to generate
events for every source line, or just on function call/return. It defaults to
<tt class="docutils literal"><span class="pre">0</span></tt> (only log function call/return). The argument <em>linetimings</em> specifies
whether to record timing information. It defaults to <tt class="docutils literal"><span class="pre">1</span></tt> (store timing
information).</dd></dl>
<div class="section" id="profile-objects">
<span id="hotshot-objects"></span><h2>27.5.1. Profile Objects<a class="headerlink" href="#profile-objects" title="Permalink to this headline">¶</a></h2>
<p>Profile objects have the following methods:</p>
<dl class="method">
<dt id="hotshot.Profile.addinfo">
<tt class="descclassname">Profile.</tt><tt class="descname">addinfo</tt><big>(</big><em>key</em>, <em>value</em><big>)</big><a class="headerlink" href="#hotshot.Profile.addinfo" title="Permalink to this definition">¶</a></dt>
<dd>Add an arbitrary labelled value to the profile output.</dd></dl>
<dl class="method">
<dt id="hotshot.Profile.close">
<tt class="descclassname">Profile.</tt><tt class="descname">close</tt><big>(</big><big>)</big><a class="headerlink" href="#hotshot.Profile.close" title="Permalink to this definition">¶</a></dt>
<dd>Close the logfile and terminate the profiler.</dd></dl>
<dl class="method">
<dt id="hotshot.Profile.fileno">
<tt class="descclassname">Profile.</tt><tt class="descname">fileno</tt><big>(</big><big>)</big><a class="headerlink" href="#hotshot.Profile.fileno" title="Permalink to this definition">¶</a></dt>
<dd>Return the file descriptor of the profiler’s log file.</dd></dl>
<dl class="method">
<dt id="hotshot.Profile.run">
<tt class="descclassname">Profile.</tt><tt class="descname">run</tt><big>(</big><em>cmd</em><big>)</big><a class="headerlink" href="#hotshot.Profile.run" title="Permalink to this definition">¶</a></dt>
<dd>Profile an <a class="reference external" href="../reference/simple_stmts.html#exec"><tt class="xref docutils literal"><span class="pre">exec</span></tt></a>-compatible string in the script environment. The
globals from the <a title="The environment where the top-level script is run." class="reference external" href="__main__.html#module-__main__"><tt class="xref docutils literal"><span class="pre">__main__</span></tt></a> module are used as both the globals and locals
for the script.</dd></dl>
<dl class="method">
<dt id="hotshot.Profile.runcall">
<tt class="descclassname">Profile.</tt><tt class="descname">runcall</tt><big>(</big><em>func</em>, <em>*args</em>, <em>**keywords</em><big>)</big><a class="headerlink" href="#hotshot.Profile.runcall" title="Permalink to this definition">¶</a></dt>
<dd>Profile a single call of a callable. Additional positional and keyword arguments
may be passed along; the result of the call is returned, and exceptions are
allowed to propagate cleanly, while ensuring that profiling is disabled on the
way out.</dd></dl>
<dl class="method">
<dt id="hotshot.Profile.runctx">
<tt class="descclassname">Profile.</tt><tt class="descname">runctx</tt><big>(</big><em>cmd</em>, <em>globals</em>, <em>locals</em><big>)</big><a class="headerlink" href="#hotshot.Profile.runctx" title="Permalink to this definition">¶</a></dt>
<dd>Evaluate an <a class="reference external" href="../reference/simple_stmts.html#exec"><tt class="xref docutils literal"><span class="pre">exec</span></tt></a>-compatible string in a specific environment. The
string is compiled before profiling begins.</dd></dl>
<dl class="method">
<dt id="hotshot.Profile.start">
<tt class="descclassname">Profile.</tt><tt class="descname">start</tt><big>(</big><big>)</big><a class="headerlink" href="#hotshot.Profile.start" title="Permalink to this definition">¶</a></dt>
<dd>Start the profiler.</dd></dl>
<dl class="method">
<dt id="hotshot.Profile.stop">
<tt class="descclassname">Profile.</tt><tt class="descname">stop</tt><big>(</big><big>)</big><a class="headerlink" href="#hotshot.Profile.stop" title="Permalink to this definition">¶</a></dt>
<dd>Stop the profiler.</dd></dl>
</div>
<div class="section" id="module-hotshot.stats">
<h2>27.5.2. Using hotshot data<a class="headerlink" href="#module-hotshot.stats" title="Permalink to this headline">¶</a></h2>
<p class="versionadded">
<span class="versionmodified">New in version 2.2.</span></p>
<p>This module loads hotshot profiling data into the standard <a title="Statistics object for use with the profiler." class="reference external" href="profile.html#module-pstats"><tt class="xref docutils literal"><span class="pre">pstats</span></tt></a> Stats
objects.</p>
<dl class="function">
<dt id="hotshot.stats.load">
<tt class="descclassname">hotshot.stats.</tt><tt class="descname">load</tt><big>(</big><em>filename</em><big>)</big><a class="headerlink" href="#hotshot.stats.load" title="Permalink to this definition">¶</a></dt>
<dd>Load hotshot data from <em>filename</em>. Returns an instance of the
<a title="pstats.Stats" class="reference external" href="profile.html#pstats.Stats"><tt class="xref docutils literal"><span class="pre">pstats.Stats</span></tt></a> class.</dd></dl>
<div class="admonition-see-also admonition seealso">
<p class="first admonition-title">See also</p>
<dl class="last docutils">
<dt>Module <tt class="xref docutils literal"><span class="pre">profile</span></tt></dt>
<dd>The <tt class="xref docutils literal"><span class="pre">profile</span></tt> module’s <tt class="xref docutils literal"><span class="pre">Stats</span></tt> class</dd>
</dl>
</div>
</div>
<div class="section" id="example-usage">
<span id="hotshot-example"></span><h2>27.5.3. Example Usage<a class="headerlink" href="#example-usage" title="Permalink to this headline">¶</a></h2>
<p>Note that this example runs the Python “benchmark” pystones. It can take some
time to run, and will produce large output files.</p>
<div class="highlight-python"><div class="highlight"><pre><span class="gp">>>> </span><span class="kn">import</span> <span class="nn">hotshot</span><span class="o">,</span> <span class="nn">hotshot.stats</span><span class="o">,</span> <span class="nn">test.pystone</span>
<span class="gp">>>> </span><span class="n">prof</span> <span class="o">=</span> <span class="n">hotshot</span><span class="o">.</span><span class="n">Profile</span><span class="p">(</span><span class="s">"stones.prof"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">benchtime</span><span class="p">,</span> <span class="n">stones</span> <span class="o">=</span> <span class="n">prof</span><span class="o">.</span><span class="n">runcall</span><span class="p">(</span><span class="n">test</span><span class="o">.</span><span class="n">pystone</span><span class="o">.</span><span class="n">pystones</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">prof</span><span class="o">.</span><span class="n">close</span><span class="p">()</span>
<span class="gp">>>> </span><span class="n">stats</span> <span class="o">=</span> <span class="n">hotshot</span><span class="o">.</span><span class="n">stats</span><span class="o">.</span><span class="n">load</span><span class="p">(</span><span class="s">"stones.prof"</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">stats</span><span class="o">.</span><span class="n">strip_dirs</span><span class="p">()</span>
<span class="gp">>>> </span><span class="n">stats</span><span class="o">.</span><span class="n">sort_stats</span><span class="p">(</span><span class="s">'time'</span><span class="p">,</span> <span class="s">'calls'</span><span class="p">)</span>
<span class="gp">>>> </span><span class="n">stats</span><span class="o">.</span><span class="n">print_stats</span><span class="p">(</span><span class="mi">20</span><span class="p">)</span>
<span class="go"> 850004 function calls in 10.090 CPU seconds</span>
<span class="go"> Ordered by: internal time, call count</span>
<span class="go"> ncalls tottime percall cumtime percall filename:lineno(function)</span>
<span class="go"> 1 3.295 3.295 10.090 10.090 pystone.py:79(Proc0)</span>
<span class="go"> 150000 1.315 0.000 1.315 0.000 pystone.py:203(Proc7)</span>
<span class="go"> 50000 1.313 0.000 1.463 0.000 pystone.py:229(Func2)</span>
<span class="go"> .</span>
<span class="go"> .</span>
<span class="go"> .</span>
</pre></div>
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<ul>
<li><a class="reference external" href="#">27.5. <tt class="docutils literal"><span class="pre">hotshot</span></tt> — High performance logging profiler</a><ul>
<li><a class="reference external" href="#profile-objects">27.5.1. Profile Objects</a></li>
<li><a class="reference external" href="#module-hotshot.stats">27.5.2. Using hotshot data</a></li>
<li><a class="reference external" href="#example-usage">27.5.3. Example Usage</a></li>
</ul>
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