1powertop(1M) System Administration Commands powertop(1M)
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6 powertop - report and analyze events that affect power management
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9 powertop [-c processor_id] [-d count] [-t interval] [-v] [-h]
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13 PowerTOP is an observability tool that shows how effectively the system
14 is taking advantage of the CPU's power management features. By running
15 the tool on an otherwise idle system, the user can see for how long the
16 CPU is running at dif- ferent power states. Ideally, an unutilized
17 (idle) system spends 100% of its time running at the lowest power
18 state, but because of background user and kernel activity (random soft‐
19 ware periodically waking to poll status), idle systems can consume more
20 power than they should.
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23 The tool analyzes system activity periodically and displays a summary
24 of how long the processor is executing at each supported power state.
25 It also displays the top activities responsible for causing the CPU to
26 wake up and use more energy. This report allows the user to identify
27 and diagnose problematic areas of the system and optimize its power
28 efficiency.
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31 PowerTOP averages the amount of activity that is preventing the CPU
32 from entering a lower power state and presents it on the "Wakeups-from-
33 idle per second" field. This value represents the total number of wake-
34 ups divided by the current interval. Notice that not all events are
35 displayed on the screen at all times.
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38 During execution, a user can force a refresh of the analysis by press‐
39 ing the R key. The interval time is restored to the default or to a
40 specified value. To quit the application, the user must press the Q
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44 If you are running as root (superuser) or in the Primary Administrator
45 role, the tool makes suggestions as how the system can be improved from
46 a power management perspective.
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49 PowerTOP allows you to freeze each of its three subwindows, enabling
50 you to better analyze each subwindow's contents. when you have three
51 different DTrace scripts running at the same time, freezing subwindows
52 lowers CPU consumption . This feature is activated by pressing the i,
53 f, or e key while the tool running. Pressing one of these keys freezes
54 the idle, frequency, or event report, respectively. Pressing it once
55 more, unfreezes it. This feature is most useful when invoked while the
56 application being analyzed is running.
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59 PowerTOP runs on xVM(5) domains. However, the report for idle state
60 transitions might or might not be accurate as the physical CPU can be
61 shared by different virtual CPUs. Both wakeup count and event report
62 displays information regarding the current virtualized environment.
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65 The following options are supported:
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67 -c [processor_id]
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69 Specifies which CPU the tool should observe.
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72 -d [count]
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74 Dumps the results of count analysis of system activity to the
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78 -h
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80 Displays the command's usage.
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83 -t [interval]
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85 Specifies the interval, in seconds, at which the tool analyzes the
86 system. The possible values are between 1 and 100; the default is 5
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90 -v
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92 Switches to verbose mode, including noting firings of the kernel
93 cyclic subsystem in the event report.
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97 Example 1 Setting the Interval
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100 The following command sets the interval to two seconds.
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103 % powertop -t 2
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107 Example 2 Analyzing and Dumping System Activity
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110 The following command analyzes and dumps system activity to the stan‐
111 dard output four times.
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114 % powertop -d 4
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118 Example 3 Reporting Cyclic Subsystem Activity
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121 The following command reports cyclic subsystem activity.
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124 % powertop -v
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128 Example 4 Analyzing Activity on a Specific Processor
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131 The following command runs PowerTOP and only displays data for CPU 3:
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134 % powertop -c 3
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141 Successful operation.
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146 An error occurred.
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151 Incorrect usage.
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155 See attributes(5) for descriptions of the following attributes:
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160 ┌─────────────────────────────┬─────────────────────────────┐
161 │ ATTRIBUTE TYPE │ ATTRIBUTE VALUE │
162 ├─────────────────────────────┼─────────────────────────────┤
163 │Architecture │x86, SPARC │
164 ├─────────────────────────────┼─────────────────────────────┤
165 │Availability │SUNWpowertop │
166 ├─────────────────────────────┼─────────────────────────────┤
167 │Interface Stability │Volatile │
168 └─────────────────────────────┴─────────────────────────────┘
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171 kstat(1M), pmconfig(1M), powerd(1M), psrinfo(1M), uadmin(2), libdev‐
172 info(3LIB), attributes(5), xVM(5), cpr(7), pm(7D), pm-components(9P),
173 removable-media(9P)
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176 Among non-SunOS man pages, xscreensaver(1) and dtpower(1M).
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179 You must have DTrace privileges to run PowerTOP and root (superuser)
180 privileges or assume the Primary Administrator role for the tool to
181 suggest improvements to the system.
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185SunOS 5.11 19 May 2009 powertop(1M)