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 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 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 executable command is forked and upon its exit, sta-
	   tistics 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(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@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)