cpupowerutils - cpufrequtils extended with quite some features

CPU power consumption vs performance tuning is no longer
limited to CPU frequency switching anymore: deep sleep states,
traditional dynamic frequency scaling and hidden turbo/boost
frequencies are tied close together and depend on each other.
The first two exist on different architectures like PPC, Itanium and
ARM, the latter (so far) only on X86. On X86 the APU (CPU+GPU) will
only run most efficiently if CPU and GPU has proper power management
in place.

Users and Developers want to have *one* tool to get an overview what
their system supports and to monitor and debug CPU power management
in detail. The tool should compile and work on as many architectures
as possible.

Once this tool stabilizes a bit, it is intended to replace the
Intel-specific tools in tools/power/x86

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>

1 files changed, 179 insertions, 0 deletions

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+.TH CPUPOWER\-MONITOR "1" "22/02/2011" "" "cpupower Manual"
+.SH NAME
+cpupower\-monitor \- Report processor frequency and idle statistics
+.SH SYNOPSIS
+.ft B
+.B cpupower monitor
+.RB "\-l"
+
+.B cpupower monitor
+.RB [ "\-m <mon1>," [ "<mon2>,..." ] ]
+.RB [ "\-i seconds" ]
+.br
+.B cpupower monitor
+.RB [ "\-m <mon1>," [ "<mon2>,..." ] ]
+.RB command
+.br
+.SH DESCRIPTION
+\fBcpupower-monitor \fP reports processor topology, frequency and idle power
+state statistics. Either \fBcommand\fP is forked and
+statistics are printed upon its completion, or statistics are printed periodically.
+
+\fBcpupower-monitor \fP implements independent processor sleep state and
+frequency counters. Some are retrieved from kernel statistics, some are
+directly reading out hardware registers. Use \-l to get an overview which are
+supported on your system.
+
+.SH Options
+.PP
+\-l
+.RS 4
+List available monitors on your system. Additional details about each monitor
+are shown:
+.RS 2
+.IP \(bu
+The name in quotation marks which can be passed to the \-m parameter.
+.IP \(bu
+The number of different counters the monitor supports in brackets.
+.IP \(bu
+The amount of time in seconds the counters might overflow, due to
+implementation constraints.
+.IP \(bu
+The name and a description of each counter and its processor hierarchy level
+coverage in square brackets:
+.RS 4
+.IP \(bu
+[T] \-> Thread
+.IP \(bu
+[C] \-> Core
+.IP \(bu
+[P] \-> Processor Package (Socket)
+.IP \(bu
+[M] \-> Machine/Platform wide counter
+.RE
+.RE
+.RE
+.PP
+\-m <mon1>,<mon2>,...
+.RS 4
+Only display specific monitors. Use the monitor string(s) provided by \-l option.
+.RE
+.PP
+\-i seconds
+.RS 4
+Measure intervall.
+.RE
+.PP
+command
+.RS 4
+Measure idle and frequency characteristics of an arbitrary command/workload.
+The executable \fBcommand\fP is forked and upon its exit, statistics gathered since it was
+forked are displayed.
+.RE
+.PP
+\-v
+.RS 4
+Increase verbosity if the binary was compiled with the DEBUG option set.
+.RE
+
+.SH MONITOR DESCRIPTIONS
+.SS "Idle_Stats"
+Shows statistics of the cpuidle kernel subsystem. Values are retrieved from
+/sys/devices/system/cpu/cpu*/cpuidle/state*/.
+The kernel updates these values every time an idle state is entered or
+left. Therefore there can be some inaccuracy when cores are in an idle
+state for some time when the measure starts or ends. In worst case it can happen
+that one core stayed in an idle state for the whole measure time and the idle
+state usage time as exported by the kernel did not get updated. In this case
+a state residency of 0 percent is shown while it was 100.
+
+.SS "Mperf"
+The name comes from the aperf/mperf (average and maximum) MSR registers used
+which are available on recent X86 processors. It shows the average frequency
+(including boost frequencies).
+The fact that on all recent hardware the mperf timer stops ticking in any idle
+state it is also used to show C0 (processor is active) and Cx (processor is in
+any sleep state) times. These counters do not have the inaccuracy restrictions
+the "Idle_Stats" counters may show.
+May work poorly on Linux-2.6.20 through 2.6.29, as the \fBacpi-cpufreq \fP
+kernel frequency driver periodically cleared aperf/mperf registers in those
+kernels.
+
+.SS "Nehalem" "SandyBridge"
+Intel Core and Package sleep state counters.
+Threads (hyperthreaded cores) may not be able to enter deeper core states if
+its sibling is utilized.
+Deepest package sleep states may in reality show up as machine/platform wide
+sleep states and can only be entered if all cores are idle. Look up Intel
+manuals (some are provided in the References section) for further details.
+
+.SS "Ontario" "Liano"
+AMD laptop and desktop processor (family 12h and 14h) sleep state counters.
+The registers are accessed via PCI and therefore can still be read out while
+cores have been offlined.
+
+There is one special counter: NBP1 (North Bridge P1).
+This one always returns 0 or 1, depending on whether the North Bridge P1
+power state got entered at least once during measure time.
+Being able to enter NBP1 state also depends on graphics power management.
+Therefore this counter can be used to verify whether the graphics' driver
+power management is working as expected.
+
+.SH EXAMPLES
+
+cpupower monitor -l" may show:
+.RS 4
+Monitor "Mperf" (3 states) \- Might overflow after 922000000 s
+
+   ...
+
+Monitor "Idle_Stats" (3 states) \- Might overflow after 4294967295 s
+
+   ...
+
+.RE
+cpupower monitor \-m "Idle_Stats,Mperf" scp /tmp/test /nfs/tmp
+
+Monitor the scp command, show both Mperf and Idle_Stats states counter
+statistics, but in exchanged order.
+
+
+
+.RE
+Be careful that the typical command to fully utilize one CPU by doing:
+
+cpupower monitor cat /dev/zero >/dev/null
+
+Does not work as expected, because the measured output is redirected to
+/dev/null. This could get workarounded by putting the line into an own, tiny
+shell script. Hit CTRL\-c to terminate the command and get the measure output
+displayed.
+
+.SH REFERENCES
+"BIOS and Kernel Developer’s Guide (BKDG) for AMD Family 14h Processors"
+http://support.amd.com/us/Processor_TechDocs/43170.pdf
+
+"Intel® Turbo Boost Technology
+in Intel® Core™ Microarchitecture (Nehalem) Based Processors"
+http://download.intel.com/design/processor/applnots/320354.pdf
+
+"Intel® 64 and IA-32 Architectures Software Developer's Manual
+Volume 3B: System Programming Guide"
+http://www.intel.com/products/processor/manuals
+
+.SH FILES
+.ta
+.nf
+/dev/cpu/*/msr
+/sys/devices/system/cpu/cpu*/cpuidle/state*/.
+.fi
+
+.SH "SEE ALSO"
+powertop(8), msr(4), vmstat(8)
+.PP
+.SH AUTHORS
+.nf
+Written by Thomas Renninger <trenn@suse.de>
+
+Nehalem, SandyBridge monitors and command passing
+based on turbostat.8 from Len Brown <len.brown@intel.com>