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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 | <?xml version="1.0" encoding="UTF-8" standalone="no"?> <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd"><html xmlns="http://www.w3.org/1999/xhtml"><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8" /><title xmlns:d="http://docbook.org/ns/docbook">5.3.2. Call Graph Tracing</title><link rel="stylesheet" type="text/css" href="Common_Content/css/default.css" /><link rel="stylesheet" media="print" href="Common_Content/css/print.css" type="text/css" /><meta xmlns:d="http://docbook.org/ns/docbook" name="generator" content="publican v4.1.3" /><meta xmlns:d="http://docbook.org/ns/docbook" name="package" content="SystemTap-SystemTap_Beginners_Guide-2.7-en-US-2.0-1" /><link rel="home" href="index.html" title="SystemTap Beginners Guide" /><link rel="up" href="mainsect-profiling.html" title="5.3. Profiling" /><link rel="prev" href="mainsect-profiling.html" title="5.3. Profiling" /><link rel="next" href="threadtimessect.html" title="5.3.3. Determining Time Spent in Kernel and User Space" /></head><body><p id="title"><a class="left" href="https://fedorahosted.org/publican"><img alt="Product Site" src="Common_Content/images//image_left.png" /></a><a class="right" href="https://fedorahosted.org/publican"><img alt="Documentation Site" src="Common_Content/images//image_right.png" /></a></p><ul class="docnav top"><li class="previous"><a accesskey="p" href="mainsect-profiling.html"><strong>Prev</strong></a></li><li class="home">SystemTap Beginners Guide</li><li class="next"><a accesskey="n" href="threadtimessect.html"><strong>Next</strong></a></li></ul><div xml:lang="en-US" class="section" lang="en-US"><div class="titlepage"><div><div><h3 class="title"><a id="paracallgraph"> </a>5.3.2. Call Graph Tracing</h3></div></div></div><a id="idm47723001724816" class="indexterm"></a><a id="idm47722995805568" class="indexterm"></a><a id="idm47722952022912" class="indexterm"></a><a id="idm47723005498144" class="indexterm"></a><a id="idm47722988587600" class="indexterm"></a><a id="idm47722954482112" class="indexterm"></a><a id="idm47722953688992" class="indexterm"></a><div class="para"> This section describes how to trace incoming and outgoing function calls. </div><div class="para"><div xmlns:d="http://docbook.org/ns/docbook" class="title">para-callgraph.stp</div> <pre class="programlisting">#! /usr/bin/env stap function trace(entry_p, extra) { %( $# > 1 %? if (tid() in trace) %) printf("%s%s%s %s\n", thread_indent (entry_p), (entry_p>0?"->":"<-"), ppfunc (), extra) } %( $# > 1 %? global trace probe $2.call { trace[tid()] = 1 } probe $2.return { delete trace[tid()] } %) probe $1.call { trace(1, $$parms) } probe $1.return { trace(-1, $$return) } </pre> </div><a id="idm47722994473136" class="indexterm"></a><a id="idm47722956353968" class="indexterm"></a><a id="idm47722951594144" class="indexterm"></a><a id="idm47722987631728" class="indexterm"></a><div class="para"> <a class="xref" href="paracallgraph.html#scriptcallgraph">para-callgraph.stp</a> takes two command-line arguments: </div><a id="idm47722955556320" class="indexterm"></a><a id="idm47722994699280" class="indexterm"></a><a id="idm47722957309792" class="indexterm"></a><div xmlns:d="http://docbook.org/ns/docbook" class="itemizedlist"><ul><li class="listitem"><div class="para"> The function/s whose entry/exit call you'd like to trace (<code class="command">$1</code>). </div></li><li class="listitem"><div class="para"> A second optional <em class="firstterm">trigger function</em> (<code class="command">$2</code>), which enables or disables tracing on a per-thread basis. Tracing in each thread will continue as long as the trigger function has not exited yet. </div></li></ul></div><a id="idm47722988605120" class="indexterm"></a><a id="idm47723004502208" class="indexterm"></a><a id="idm47722999823648" class="indexterm"></a><div class="para"> <a class="xref" href="paracallgraph.html#scriptcallgraph">para-callgraph.stp</a> uses <code class="command">thread_indent()</code>; as such, its output contains the timestamp, process name, and thread ID of <code class="command">$1</code> (that is, the probe function you are tracing). For more information about <code class="command">thread_indent()</code>, refer to its entry in <a class="xref" href="systemtapscript-handler.html#systemtapscript-functions">SystemTap Functions</a>. </div><div class="para"> The following example contains an excerpt from the output for <code class="command">stap para-callgraph.stp 'kernel.function("*@fs/*.c")' 'kernel.function("sys_read")'</code>: </div><div class="example"><a id="paracallgraphoutput"> </a><p class="title"><strong>Example 5.14. <a class="xref" href="paracallgraph.html#scriptcallgraph">para-callgraph.stp</a> Sample Output</strong></p><div class="example-contents"><pre class="screen">[...] 267 gnome-terminal(2921): <-do_sync_read return=0xfffffffffffffff5 269 gnome-terminal(2921):<-vfs_read return=0xfffffffffffffff5 0 gnome-terminal(2921):->fput file=0xffff880111eebbc0 2 gnome-terminal(2921):<-fput 0 gnome-terminal(2921):->fget_light fd=0x3 fput_needed=0xffff88010544df54 3 gnome-terminal(2921):<-fget_light return=0xffff8801116ce980 0 gnome-terminal(2921):->vfs_read file=0xffff8801116ce980 buf=0xc86504 count=0x1000 pos=0xffff88010544df48 4 gnome-terminal(2921): ->rw_verify_area read_write=0x0 file=0xffff8801116ce980 ppos=0xffff88010544df48 count=0x1000 7 gnome-terminal(2921): <-rw_verify_area return=0x1000 12 gnome-terminal(2921): ->do_sync_read filp=0xffff8801116ce980 buf=0xc86504 len=0x1000 ppos=0xffff88010544df48 15 gnome-terminal(2921): <-do_sync_read return=0xfffffffffffffff5 18 gnome-terminal(2921):<-vfs_read return=0xfffffffffffffff5 0 gnome-terminal(2921):->fput file=0xffff8801116ce980</pre></div></div></div><ul class="docnav"><li class="previous"><a accesskey="p" href="mainsect-profiling.html"><strong>Prev</strong>5.3. Profiling</a></li><li class="up"><a accesskey="u" href="#"><strong>Up</strong></a></li><li class="home"><a accesskey="h" href="index.html"><strong>Home</strong></a></li><li class="next"><a accesskey="n" href="threadtimessect.html"><strong>Next</strong>5.3.3. Determining Time Spent in Kernel and User ...</a></li></ul></body></html>
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