powertop(1M) System Administration Commands powertop(1M)NAMEpowertop - report and analyze events that affect power management
SYNOPSISpowertop [-c processor_id] [-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 spends 100% of its time running at the lowest power
state, but because of background user and kernel activity (random soft‐
ware 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 press‐
ing the R key. The interval time is 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 makes suggestions as how the system can be improved from
a power management perspective.
PowerTOP allows you to freeze each of its three subwindows, enabling
you to better analyze each subwindow's contents. When you have three
different DTrace scripts running at the same time, freezing subwindows
lowers CPU consumption . This feature is activated by pressing the i,
f, or e key while the tool running. Pressing one of these keys freezes
the idle, frequency, or event report, respectively. Pressing it once
more, unfreezes it. This feature is most useful when invoked while the
application being analyzed is running.
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
displays information regarding the current virtualized environment.
OPTIONS
The following options are supported:
-c [processor_id]
Specifies which CPU the tool should observe.
-d [count]
Dumps the results of count analysis of system activity to the
screen.
-h
Displays the command's usage.
-t [interval]
Specifies the interval, in seconds, at which the tool analyzes the
system. The possible values are in the range of 1 through 30; the
default is 5 seconds.
-v
Switches to verbose mode, including noting firings of the kernel
cyclic subsystem in the event report.
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 stan‐
dard output four times.
% powertop-d 4
Example 3 Reporting Cyclic Subsystem Activity
The following command reports cyclic subsystem activity.
% powertop-v
Example 4 Analyzing Activity on a Specific Processor
The following command runs PowerTOP and only displays data for CPU 3:
% powertop-c 3
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 │diagnostic/powertop │
├─────────────────────────────┼─────────────────────────────┤
│Interface Stability │Volatile │
└─────────────────────────────┴─────────────────────────────┘
SEE ALSOkstat(1M), pmconfig(1M), powerd(1M), psrinfo(1M), uadmin(2), libdev‐
info(3LIB), attributes(5), xVM(5), cpr(7), pm(7D), pm-components(9P),
removable-media(9P)
Among non-SunOS man pages, xscreensaver(1) and dtpower(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.
SunOS 5.11 15 Oct 2009 powertop(1M)
