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@@ -1,6 +1,6 @@
1<?xml version="1.0" encoding="UTF-8" standalone="no"?> 1<?xml version="1.0" encoding="UTF-8" standalone="no"?>
2<!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">5.3.4. Monitoring Polling Applications</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="not publican" /><meta xmlns:d="http://docbook.org/ns/docbook" name="package" content="" /><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="threadtimessect.html" title="5.3.3. Determining Time Spent in Kernel and User Space" /><link rel="next" href="topsyssect.html" title="5.3.5. Tracking Most Frequently Used System Calls" /></head><body><p id="title"></p><ul class="docnav top"><li class="previous"><a accesskey="p" href="threadtimessect.html"><strong>Prev</strong></a></li><li class="home">SystemTap Beginners Guide</li><li class="next"><a accesskey="n" href="topsyssect.html"><strong>Next</strong></a></li></ul><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="timeoutssect"> 2<!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">5.3.4. Monitoring Polling Applications</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="not publican" /><meta xmlns:d="http://docbook.org/ns/docbook" name="package" content="" /><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="threadtimessect.html" title="5.3.3. Determining Time Spent in Kernel and User Space" /><link rel="next" href="topsyssect.html" title="5.3.5. Tracking Most Frequently Used System Calls" /></head><body><p id="title"></p><ul class="docnav top"><li class="previous"><a accesskey="p" href="threadtimessect.html"><strong>Prev</strong></a></li><li class="home">SystemTap Beginners Guide</li><li class="next"><a accesskey="n" href="topsyssect.html"><strong>Next</strong></a></li></ul><div class="section"><div class="titlepage"><div><div><h3 class="title"><a id="timeoutssect">
3 ⁠</a>5.3.4. Monitoring Polling Applications</h3></div></div></div><a id="idm46926933762144" class="indexterm"></a><a id="idm46926929106320" class="indexterm"></a><a id="idm46926928800208" class="indexterm"></a><a id="idm46926932891968" class="indexterm"></a><div class="para"> 3 ⁠</a>5.3.4. Monitoring Polling Applications</h3></div></div></div><a id="idm140217032561392" class="indexterm"></a><a id="idm140217034260992" class="indexterm"></a><a id="idm140217036558832" class="indexterm"></a><a id="idm140217043144704" class="indexterm"></a><div class="para">
4 This section describes how to identify and monitor which applications are polling. Doing so allows you to track 4 This section describes how to identify and monitor which applications are polling. Doing so allows you to track
5 unnecessary or excessive polling, which can help you pinpoint areas for improvement in terms of CPU usage 5 unnecessary or excessive polling, which can help you pinpoint areas for improvement in terms of CPU usage
6 and power savings. 6 and power savings.
@@ -19,80 +19,72 @@ probe syscall.poll, syscall.epoll_wait {
19} 19}
20 20
21probe syscall.poll.return { 21probe syscall.poll.return {
22 p = pid() 22 if ($return == 0 &amp;&amp; to[pid()] &gt; 0 ) {
23 if ($return == 0 &amp;&amp; to[p] &gt; 0 ) { 23 poll_timeout[pid()]++
24 poll_timeout[p]++ 24 timeout_count[pid()]++
25 timeout_count[p]++ 25 process[pid()] = execname()
26 process[p] = execname() 26 delete to[pid()]
27 delete to[p]
28 } 27 }
29} 28}
30 29
31probe syscall.epoll_wait.return { 30probe syscall.epoll_wait.return {
32 p = pid() 31 if ($return == 0 &amp;&amp; to[pid()] &gt; 0 ) {
33 if ($return == 0 &amp;&amp; to[p] &gt; 0 ) { 32 epoll_timeout[pid()]++
34 epoll_timeout[p]++ 33 timeout_count[pid()]++
35 timeout_count[p]++
36 process[p] = execname() 34 process[p] = execname()
37 delete to[p] 35 delete to[pid()]
38 } 36 }
39} 37}
40 38
41probe syscall.select.return { 39probe syscall.select.return {
42 if ($return == 0) { 40 if ($return == 0) {
43 p = pid() 41 select_timeout[pid()]++
44 select_timeout[p]++ 42 timeout_count[pid()]++
45 timeout_count[p]++ 43 process[pid()] = execname()
46 process[p] = execname()
47 } 44 }
48} 45}
49 46
50probe syscall.futex.return { 47probe syscall.futex.return {
51 if (errno_str($return) == "ETIMEDOUT") { 48 if (errno_str($return) == "ETIMEDOUT") {
52 p = pid() 49 futex_timeout[pid()]++
53 futex_timeout[p]++ 50 timeout_count[pid()]++
54 timeout_count[p]++ 51 process[pid()] = execname()
55 process[p] = execname()
56 } 52 }
57} 53}
58 54
59probe syscall.nanosleep.return { 55probe syscall.nanosleep.return {
60 if ($return == 0) { 56 if ($return == 0) {
61 p = pid() 57 nanosleep_timeout[pid()]++
62 nanosleep_timeout[p]++ 58 timeout_count[pid()]++
63 timeout_count[p]++ 59 process[pid()] = execname()
64 process[p] = execname()
65 } 60 }
66} 61}
67 62
68probe kernel.function("it_real_fn") { 63probe kernel.function("it_real_fn") {
69 p = pid() 64 itimer_timeout[pid()]++
70 itimer_timeout[p]++ 65 timeout_count[pid()]++
71 timeout_count[p]++ 66 process[pid()] = execname()
72 process[p] = execname()
73} 67}
74 68
75probe syscall.rt_sigtimedwait.return { 69probe syscall.rt_sigtimedwait.return {
76 if (errno_str($return) == "EAGAIN") { 70 if (errno_str($return) == "EAGAIN") {
77 p = pid() 71 signal_timeout[pid()]++
78 signal_timeout[p]++ 72 timeout_count[pid()]++
79 timeout_count[p]++ 73 process[pid()] = execname()
80 process[p] = execname()
81 } 74 }
82} 75}
83 76
84probe syscall.exit { 77probe syscall.exit {
85 p = pid() 78 if (pid() in process) {
86 if (p in process) { 79 delete process[pid()]
87 delete process[p] 80 delete timeout_count[pid()]
88 delete timeout_count[p] 81 delete poll_timeout[pid()]
89 delete poll_timeout[p] 82 delete epoll_timeout[pid()]
90 delete epoll_timeout[p] 83 delete select_timeout[pid()]
91 delete select_timeout[p] 84 delete itimer_timeout[pid()]
92 delete itimer_timeout[p] 85 delete futex_timeout[pid()]
93 delete futex_timeout[p] 86 delete nanosleep_timeout[pid()]
94 delete nanosleep_timeout[p] 87 delete signal_timeout[pid()]
95 delete signal_timeout[p]
96 } 88 }
97} 89}
98 90
@@ -113,7 +105,7 @@ probe timer.s(1) {
113 of the following system calls completed 105 of the following system calls completed
114 due to time expiring rather than due to an actual event 106 due to time expiring rather than due to an actual event
115 occurring: 107 occurring:
116 </div><div xmlns:d="http://docbook.org/ns/docbook" class="itemizedlist"><ul><li class="listitem"><div class="para"><code class="command">poll</code></div></li><li class="listitem"><div class="para"><code class="command">select</code></div></li><li class="listitem"><div class="para"><code class="command">epoll</code></div></li><li class="listitem"><div class="para"><code class="command">itimer</code></div></li><li class="listitem"><div class="para"><code class="command">futex</code></div></li><li class="listitem"><div class="para"><code class="command">nanosleep</code></div></li><li class="listitem"><div class="para"><code class="command">signal</code></div></li></ul></div><a id="idm46926930658304" class="indexterm"></a><a id="idm46926930469184" class="indexterm"></a><a id="idm46926930780416" class="indexterm"></a><div class="example"><a id="timeoutsoutput"> 108 </div><div xmlns:d="http://docbook.org/ns/docbook" class="itemizedlist"><ul><li class="listitem"><div class="para"><code class="command">poll</code></div></li><li class="listitem"><div class="para"><code class="command">select</code></div></li><li class="listitem"><div class="para"><code class="command">epoll</code></div></li><li class="listitem"><div class="para"><code class="command">itimer</code></div></li><li class="listitem"><div class="para"><code class="command">futex</code></div></li><li class="listitem"><div class="para"><code class="command">nanosleep</code></div></li><li class="listitem"><div class="para"><code class="command">signal</code></div></li></ul></div><a id="idm140217034287952" class="indexterm"></a><a id="idm140217042699536" class="indexterm"></a><a id="idm140217035250592" class="indexterm"></a><div class="example"><a id="timeoutsoutput">
117 ⁠</a><p class="title"><strong>Example 5.16. <a class="xref" href="timeoutssect.html#timeouts">timeout.stp</a> Sample Output</strong></p><div class="example-contents"><pre class="screen"> uid | poll select epoll itimer futex nanosle signal| process 109 ⁠</a><p class="title"><strong>Example 5.16. <a class="xref" href="timeoutssect.html#timeouts">timeout.stp</a> Sample Output</strong></p><div class="example-contents"><pre class="screen"> uid | poll select epoll itimer futex nanosle signal| process
11828937 | 148793 0 0 4727 37288 0 0| firefox 11028937 | 148793 0 0 4727 37288 0 0| firefox
11922945 | 0 56949 0 1 0 0 0| scim-bridge 11122945 | 0 56949 0 1 0 0 0| scim-bridge
generated by cgit (git 2.34.1) at 2025-11-02 10:06:52 +0000