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CPUPOWER-MONITOR(1)             cpupower Manual            CPUPOWER-MONITOR(1)

NAME
       cpupower-monitor - Report processor frequency and idle statistics
SYNOPSIS
       cpupower monitor -l
       cpupower monitor [-c][-m <mon1>,[<mon2>,...]]  [-i seconds]
       cpupower monitor [-c][-m <mon1>,[<mon2>,...]]  command
DESCRIPTION
       cpupower-monitor   reports processor topology, frequency and idle power
       state statistics. Either command is forked and statistics  are  printed
       upon its completion, or statistics are printed periodically.
       cpupower-monitor  implements independent processor sleep state and fre-
       quency 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.

Options
       -l
           List available monitors on your system.  Additional  details  about
           each monitor are shown:
             o      The  name in quotation marks which can be passed to the -m
                    parameter.
             o      The number of different counters the monitor  supports  in
                    brackets.
             o      The amount of time in seconds the counters might overflow,
                    due to implementation constraints.
             o      The name and a description of each counter and its proces-
                    sor hierarchy level coverage in square brackets:
                 o      [T] -> Thread
                 o      [C] -> Core
                 o      [P] -> Processor Package (Socket)
                 o      [M] -> Machine/Platform wide counter
       -m <mon1>,<mon2>,...
           Only  display specific monitors. Use the monitor string(s) provided
           by -l option.
       -i seconds
           Measure intervall.
       -c
           Schedule the process on every core before starting and ending  mea-
           suring.   This  could  be needed for the Idle_Stats monitor when no
           other MSR based monitor (has to be run on the  core  that  is  mea-
           sured)  is run in parallel.  This is to wake up the processors from
           deeper sleep states and let the kernel re -account its cpuidle  (C-
           state) information before reading the cpuidle timings from sysfs.
       command
           Measure  idle  and  frequency  characteristics of an arbitrary com-
           mand/workload.  The executable command is forked and upon its exit,
           statistics gathered since it was forked are displayed.
       -v
           Increase verbosity if the binary was compiled with the DEBUG option
           set.

MONITOR DESCRIPTIONS
   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.

   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 acpi-cpufreq kernel  frequency  driver  periodi-
       cally cleared aperf/mperf registers in those kernels.

   Nehalem SandyBridge HaswellExtended
       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.  The monitors are  named  after  the  CPU
       family  where  the  sleep state capabilities got introduced and may not
       match exactly the CPU name of the platform.  For example  an  IvyBridge
       processor  has sleep state capabilities which got introduced in Nehalem
       and SandyBridge processor families.  Thus on an IvyBridge processor one
       will get Nehalem and SandyBridge sleep state monitors.  HaswellExtended
       extra package sleep state capabilities are available only in a specific
       Haswell (family 0x45) and probably also other future processors.

   Fam_12h Fam_14h
       AMD laptop and desktop processor (family 12h and 14h) sleep state coun-
       ters.  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 man-
       agement is working as expected.

EXAMPLES
       cpupower monitor -l" may show:
           Monitor "Mperf" (3 states) - Might overflow after 922000000 s
              ...
           Monitor "Idle_Stats" (3 states) - Might overflow after 4294967295 s
              ...
       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.

       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 mea-
       sure output displayed.

REFERENCES
       "BIOS and Kernel Developer's Guide (BKDG) for AMD  Family  14h  Proces-
       sors" http://support.amd.com/us/Processor_TechDocs/43170.pdf
       "Intel(R)  Turbo  Boost Technology in Intel(R) Coretm Microarchitecture
       (Nehalem)  Based  Processors"  http://download.intel.com/design/proces-
       sor/applnots/320354.pdf
       "Intel(R) 64 and IA-32 Architectures Software Developer's Manual Volume
       3B:  System  Programming  Guide"  http://www.intel.com/products/proces-
       sor/manuals

FILES
       /dev/cpu/*/msr
       /sys/devices/system/cpu/cpu*/cpuidle/state*/.

SEE ALSO
       powertop(8), msr(4), vmstat(8)
AUTHORS
       Written by Thomas Renninger <trenn AT suse.de>
       Nehalem, SandyBridge monitors and command passing
       based on turbostat.8 from Len Brown <len.brown AT intel.com>

                                  22/02/2011               CPUPOWER-MONITOR(1)