System Administration Commands powertop(1M)
NAME
powertop - report and analyze events that affect power
management
SYNOPSIS
powertop [-d count] [-t interval] [-v] [-h]
DESCRIPTION
PowerTOP is an observability tool that shows how effectively
the system is taking advantage of the CPU's power management
features. By running the tool on an otherwise idle system,
the user can see for how long the CPU is running at dif-
ferent power states. Ideally, an unutilized (idle) system
will spend 100% of its time running at the lowest power
state, but because of background user and kernel activity
(random software periodically waking to poll status), idle
systems can consume more power than they should.
The tool analyzes system activity periodically and displays
a summary of how long the processor is executing at each
supported power state. It also displays the top activities
responsible for causing the CPU to wake up and use more
energy. This report allows the user to identify and diagnose
problematic areas of the system and optimize its power effi-
ciency.
PowerTOP averages the amount of activity that is preventing
the CPU from entering a lower power state and presents it on
the "Wakeups-from-idle per second" field. This value
represents the total number of wake-ups divided by the
current interval. Notice that not all events are displayed
on the screen at all times.
During execution, a user can force a refresh of the analysis
by pressing the R key. The interval time will be restored to
the default or to a specified value. To quit the applica-
tion, the user must press the Q key.
If you are running as root (superuser) or in the Primary
Administrator role, the tool will make suggestions as how
the system can be improved from a power management perspec-
tive.
PowerTOP runs on xVM(5) domains. However, the report for
idle state transitions might or might not be accurate as the
physical CPU can be shared by different virtual CPUs. Both
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System Administration Commands powertop(1M)
wakeup count and event report will display information
regarding the current virtualized environment.
OPTIONS
The following options are supported:
-d [count]
Dumps the results of count analysis of system activity
to the screen.
-t [interval]
Specifies the interval, in seconds, at which the tool
analyzes the system. The possible values are between 1
and 100; the default is 5 seconds.
-v
Switches to verbose mode, including noting firings of
the kernel cyclic subsystem in the event report.
-h
Displays the command's usage.
EXAMPLES
Example 1 Setting the Interval
The following command sets the interval to two seconds.
% powertop -t 2
Example 2 Analyzing and Dumping System Activity
The following command analyzes and dumps system activity to
the standard output four times.
% powertop -d 4
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System Administration Commands powertop(1M)
Example 3 Reporting Cyclic Subsystem Activity
The following command reports cyclic subsystem activity.
% powertop -v
EXIT STATUS
0
Successful operation.
1
An error occurred.
2
Incorrect usage.
ATRIBUTES
See attributes(5) for descriptions of the following attri-
butes:
ATRIBUTE TYPE ATRIBUTE VALUE
Architecture x86, SPARC
Availability SUNWpowertop
Interface Stability Volatile
SEE ALSO
kstat(1M), pmconfig(1M), powerd(1M), psrinfo(1M), uadmin(2),
libdevinfo(3LIB), attributes(5), xVM(5), cpr(7), pm(7D),
pm-components(9P), removable-media(9P)
Among non-SunOS man pages, xscreensaver(1), from the
OpenWindows man pages; dtpower(1M), from the CDE man pages.
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System Administration Commands powertop(1M)
USAGE
You must have DTrace privileges to run PowerTOP and root
(superuser) privileges or assume the Primary Administrator
role for the tool to suggest improvements to the system.
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