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 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.

Options

       -l
           List  available  monitors  on  your  system. Additional details about each monitor are
           shown:

             •      The name in quotation marks which can be passed to the -m parameter.

             •      The number of different counters the monitor supports in brackets.

             •      The  amount  of  time  in  seconds  the  counters  might  overflow,  due   to
                    implementation constraints.

             •      The  name and a description of each counter and its processor hierarchy level
                    coverage in square brackets:

                 •      [T] -> Thread

                 •      [C] -> Core

                 •      [P] -> Processor Package (Socket)

                 •      [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 measuring.   This  could
           be needed for the Idle_Stats monitor when no other MSR based monitor (has to be run on
           the core that is measured) 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  command/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 periodically 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 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.

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 measure output displayed.

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

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@suse.de>

       Nehalem, SandyBridge monitors and command passing
       based on turbostat.8 from Len Brown <len.brown@intel.com>

                                            22/02/2011                        CPUPOWER-MONITOR(1)