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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 frequency counters.
       Some are retrieved from kernel statistics, some are directly reading out  hardware  regis-
       ters. 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 implementa-
		    tion constraints.

	     o	    The  name and a description of each counter and its processor 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 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 exe-
	   cutable  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 fre-
       quencies).  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 mea-
       sure  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://sup-
       port.amd.com/us/Processor_TechDocs/43170.pdf

       "Intel(R) Turbo Boost Technology in Intel(R) Coretm Microarchitecture (Nehalem) Based Pro-
       cessors" http://download.intel.com/design/processor/applnots/320354.pdf

       "Intel(R) 64 and IA-32 Architectures Software Developer's Manual Volume	3B:  System  Pro-
       gramming 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)
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