1powertop(1M)            System Administration Commands            powertop(1M)
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NAME

6       powertop - report and analyze events that affect power management
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SYNOPSIS

9       powertop [-c processor_id] [-d count] [-t interval] [-v] [-h]
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DESCRIPTION

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
41       key.
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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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OPTIONS

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
75           screen.
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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
87           seconds.
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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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EXAMPLES

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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EXIT STATUS

139       0
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141           Successful operation.
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144       1
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146           An error occurred.
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149       2
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151           Incorrect usage.
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ATTRIBUTES

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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SEE ALSO

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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USAGE

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)
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