powertop(1M) 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 run-
ning 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 unuti-
lized (idle) system will spend 100% of its time running at the lowest power state, but because of background user and kernel activity (ran-
dom 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 efficiency.
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 application, 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 perspective.
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 wakeup count and event report will display information regarding the current virtualized environ-
ment.
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
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.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE 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.
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.
SunOS 5.11 11 Sep 2008 powertop(1M)