tools/power/x86/turbostat/turbostat.8 - pub/scm/linux/kernel/git/mzx/linux - Git at Google

 .TH TURBOSTAT 8
 .SH NAME
 turbostat \- Report processor frequency and idle statistics
 .SH SYNOPSIS
 .ft B
 .B turbostat
 .RB [ Options ]
 .RB command
 .br
 .B turbostat
 .RB [ Options ]
 .RB [ "\-i interval_sec" ]
 .SH DESCRIPTION
 \fBturbostat \fP reports processor topology, frequency,
 idle power-state statistics, temperature and power on modern X86 processors.
 Either \fBcommand\fP is forked and statistics are printed
 upon its completion, or statistics are printed periodically.

 \fBturbostat \fP
 must be run on root, and
 minimally requires that the processor
 supports an "invariant" TSC, plus the APERF and MPERF MSRs.
 Additional information is reported depending on hardware counter support.

 .SS Options
 The \fB-p\fP option limits output to the 1st thread in 1st core of each package.
 .PP
 The \fB-P\fP option limits output to the 1st thread in each Package.
 .PP
 The \fB-S\fP option limits output to a 1-line System Summary for each interval.
 .PP
 The \fB-v\fP option increases verbosity.
 .PP
 The \fB-c MSR#\fP option includes the delta of the specified 32-bit MSR counter.
 .PP
 The \fB-C MSR#\fP option includes the delta of the specified 64-bit MSR counter.
 .PP
 The \fB-m MSR#\fP option includes the the specified 32-bit MSR value.
 .PP
 The \fB-M MSR#\fP option includes the the specified 64-bit MSR value.
 .PP
 The \fB-i interval_sec\fP option prints statistics every \fiinterval_sec\fP seconds.
 The default is 5 seconds.
 .PP
 The \fBcommand\fP parameter forks \fBcommand\fP and upon its exit,
 displays the statistics gathered since it was forked.
 .PP
 .SH FIELD DESCRIPTIONS
 .nf
 \fBpk\fP processor package number.
 \fBcor\fP processor core number.
 \fBCPU\fP Linux CPU (logical processor) number.
 Note that multiple CPUs per core indicate support for Intel(R) Hyper-Threading Technology.
 \fB%c0\fP percent of the interval that the CPU retired instructions.
 \fBGHz\fP average clock rate while the CPU was in c0 state.
 \fBTSC\fP average GHz that the TSC ran during the entire interval.
 \fB%c1, %c3, %c6, %c7\fP show the percentage residency in hardware core idle states.
 \fBCTMP\fP Degrees Celsius reported by the per-core Digital Thermal Sensor.
 \fBPTMP\fP Degrees Celsius reported by the per-package Package Thermal Monitor.
 \fB%pc2, %pc3, %pc6, %pc7\fP percentage residency in hardware package idle states.
 \fBPkg_W\fP Watts consumed by the whole package.
 \fBCor_W\fP Watts consumed by the core part of the package.
 \fBGFX_W\fP Watts consumed by the Graphics part of the package -- available only on client processors.
 \fBRAM_W\fP Watts consumed by the DRAM DIMMS -- available only on server processors.
 \fBPKG_%\fP percent of the interval that RAPL throttling was active on the Package.
 \fBRAM_%\fP percent of the interval that RAPL throttling was active on DRAM.
 .fi
 .PP
 .SH EXAMPLE
 Without any parameters, turbostat prints out counters ever 5 seconds.
 (override interval with "-i sec" option, or specify a command
 for turbostat to fork).

 The first row of statistics is a summary for the entire system.
 For residency % columns, the summary is a weighted average.
 For Temperature columns, the summary is the column maximum.
 For Watts columns, the summary is a system total.
 Subsequent rows show per-CPU statistics.

 .nf
 [root@sandy]# ./turbostat
 cor CPU    %c0  GHz  TSC    %c1    %c3    %c6    %c7 CTMP PTMP   %pc2   %pc3   %pc6   %pc7  Pkg_W  Cor_W GFX_W
           0.06 0.80 2.29   0.11   0.00   0.00  99.83   47   40   0.26   0.01   0.44  98.78   3.49   0.12  0.14
   0   0   0.07 0.80 2.29   0.07   0.00   0.00  99.86   40   40   0.26   0.01   0.44  98.78   3.49   0.12  0.14
   0   4   0.03 0.80 2.29   0.12
   1   1   0.04 0.80 2.29   0.25   0.01   0.00  99.71   40
   1   5   0.16 0.80 2.29   0.13
   2   2   0.05 0.80 2.29   0.06   0.01   0.00  99.88   40
   2   6   0.03 0.80 2.29   0.08
   3   3   0.05 0.80 2.29   0.08   0.00   0.00  99.87   47
   3   7   0.04 0.84 2.29   0.09
 .fi
 .SH SUMMARY EXAMPLE
 The "-s" option prints the column headers just once,
 and then the one line system summary for each sample interval.

 .nf
 [root@wsm]# turbostat -S
    %c0  GHz  TSC    %c1    %c3    %c6 CTMP   %pc3   %pc6
   1.40 2.81 3.38  10.78  43.47  44.35   42  13.67   2.09
   1.34 2.90 3.38  11.48  58.96  28.23   41  19.89   0.15
   1.55 2.72 3.38  26.73  37.66  34.07   42   2.53   2.80
   1.37 2.83 3.38  16.95  60.05  21.63   42   5.76   0.20
 .fi
 .SH VERBOSE EXAMPLE
 The "-v" option adds verbosity to the output:

 .nf
 [root@ivy]# turbostat -v
 turbostat v3.0 November 23, 2012 - Len Brown <lenb@kernel.org>
 CPUID(0): GenuineIntel 13 CPUID levels; family:model:stepping 0x6:3a:9 (6:58:9)
 CPUID(6): APERF, DTS, PTM, EPB
 RAPL: 851 sec. Joule Counter Range
 cpu0: MSR_NHM_PLATFORM_INFO: 0x81010f0012300
 16 * 100 = 1600 MHz max efficiency
 35 * 100 = 3500 MHz TSC frequency
 cpu0: MSR_NHM_SNB_PKG_CST_CFG_CTL: 0x1e008402 (UNdemote-C3, UNdemote-C1, demote-C3, demote-C1, locked: pkg-cstate-limit=2: pc6-noret)
 cpu0: MSR_NHM_TURBO_RATIO_LIMIT: 0x25262727
 37 * 100 = 3700 MHz max turbo 4 active cores
 38 * 100 = 3800 MHz max turbo 3 active cores
 39 * 100 = 3900 MHz max turbo 2 active cores
 39 * 100 = 3900 MHz max turbo 1 active cores
 cpu0: MSR_IA32_ENERGY_PERF_BIAS: 0x00000006 (balanced)
 cpu0: MSR_RAPL_POWER_UNIT: 0x000a1003 (0.125000 Watts, 0.000015 Joules, 0.000977 sec.)
 cpu0: MSR_PKG_POWER_INFO: 0x01e00268 (77 W TDP, RAPL 60 - 0 W, 0.000000 sec.)
 cpu0: MSR_PKG_POWER_LIMIT: 0x830000148268 (UNlocked)
 cpu0: PKG Limit #1: ENabled (77.000000 Watts, 1.000000 sec, clamp DISabled)
 cpu0: PKG Limit #2: ENabled (96.000000 Watts, 0.000977* sec, clamp DISabled)
 cpu0: MSR_PP0_POLICY: 0
 cpu0: MSR_PP0_POWER_LIMIT: 0x00000000 (UNlocked)
 cpu0: Cores Limit: DISabled (0.000000 Watts, 0.000977 sec, clamp DISabled)
 cpu0: MSR_PP1_POLICY: 0
 cpu0: MSR_PP1_POWER_LIMIT: 0x00000000 (UNlocked)
 cpu0: GFX Limit: DISabled (0.000000 Watts, 0.000977 sec, clamp DISabled)
 cpu0: MSR_IA32_TEMPERATURE_TARGET: 0x00691400 (105 C)
 cpu0: MSR_IA32_PACKAGE_THERM_STATUS: 0x884e0000 (27 C)
 cpu0: MSR_IA32_THERM_STATUS: 0x88560000 (19 C +/- 1)
 cpu1: MSR_IA32_THERM_STATUS: 0x88560000 (19 C +/- 1)
 cpu2: MSR_IA32_THERM_STATUS: 0x88540000 (21 C +/- 1)
 cpu3: MSR_IA32_THERM_STATUS: 0x884e0000 (27 C +/- 1)
  ...
 .fi
 The \fBmax efficiency\fP frequency, a.k.a. Low Frequency Mode, is the frequency
 available at the minimum package voltage.  The \fBTSC frequency\fP is the nominal
 maximum frequency of the processor if turbo-mode were not available.  This frequency
 should be sustainable on all CPUs indefinitely, given nominal power and cooling.
 The remaining rows show what maximum turbo frequency is possible
 depending on the number of idle cores.  Note that this information is
 not available on all processors.
 .SH FORK EXAMPLE
 If turbostat is invoked with a command, it will fork that command
 and output the statistics gathered when the command exits.
 eg. Here a cycle soaker is run on 1 CPU (see %c0) for a few seconds
 until ^C while the other CPUs are mostly idle:

 .nf
 [root@x980 lenb]# ./turbostat cat /dev/zero > /dev/null
 ^C
 cor CPU    %c0  GHz  TSC    %c1    %c3    %c6   %pc3   %pc6
           8.86 3.61 3.38  15.06  31.19  44.89   0.00   0.00
   0   0   1.46 3.22 3.38  16.84  29.48  52.22   0.00   0.00
   0   6   0.21 3.06 3.38  18.09
   1   2   0.53 3.33 3.38   2.80  46.40  50.27
   1   8   0.89 3.47 3.38   2.44
   2   4   1.36 3.43 3.38   9.04  23.71  65.89
   2  10   0.18 2.86 3.38  10.22
   8   1   0.04 2.87 3.38  99.96   0.01   0.00
   8   7  99.72 3.63 3.38   0.27
   9   3   0.31 3.21 3.38   7.64  56.55  35.50
   9   9   0.08 2.95 3.38   7.88
  10   5   1.42 3.43 3.38   2.14  30.99  65.44
  10  11   0.16 2.88 3.38   3.40
 .fi
 Above the cycle soaker drives cpu7 up its 3.6 GHz turbo limit
 while the other processors are generally in various states of idle.

 Note that cpu1 and cpu7 are HT siblings within core8.
 As cpu7 is very busy, it prevents its sibling, cpu1,
 from entering a c-state deeper than c1.

 Note that turbostat reports average GHz of 3.63, while
 the arithmetic average of the GHz column above is lower.
 This is a weighted average, where the weight is %c0.  ie. it is the total number of
 un-halted cycles elapsed per time divided by the number of CPUs.
 .SH SMI COUNTING EXAMPLE
 On Intel Nehalem and newer processors, MSR 0x34 is a System Management Mode Interrupt (SMI) counter.
 This counter is shown by default under the "SMI" column.
 .nf
 [root@x980 ~]# turbostat
 cor CPU    %c0  GHz  TSC SMI    %c1    %c3    %c6 CTMP   %pc3   %pc6
           0.11 1.91 3.38   0   1.84   0.26  97.79   29   0.82  83.87
   0   0   0.40 1.63 3.38   0  10.27   0.12  89.20   20   0.82  83.88
   0   6   0.06 1.63 3.38   0  10.61
   1   2   0.37 2.63 3.38   0   0.02   0.10  99.51   22
   1   8   0.01 1.62 3.38   0   0.39
   2   4   0.07 1.62 3.38   0   0.04   0.07  99.82   23
   2  10   0.02 1.62 3.38   0   0.09
   8   1   0.23 1.64 3.38   0   0.10   1.07  98.60   24
   8   7   0.02 1.64 3.38   0   0.31
   9   3   0.03 1.62 3.38   0   0.03   0.05  99.89   29
   9   9   0.02 1.62 3.38   0   0.05
  10   5   0.07 1.62 3.38   0   0.08   0.12  99.73   27
  10  11   0.03 1.62 3.38   0   0.13
 ^C
 .fi
 .SH NOTES

 .B "turbostat "
 must be run as root.

 .B "turbostat "
 reads hardware counters, but doesn't write them.
 So it will not interfere with the OS or other programs, including
 multiple invocations of itself.

 \fBturbostat \fP
 may work poorly on Linux-2.6.20 through 2.6.29,
 as \fBacpi-cpufreq \fPperiodically cleared the APERF and MPERF
 in those kernels.

 If the TSC column does not make sense, then
 the other numbers will also make no sense.
 Turbostat is lightweight, and its data collection is not atomic.
 These issues are usually caused by an extremely short measurement
 interval (much less than 1 second), or system activity that prevents
 turbostat from being able to run on all CPUS to quickly collect data.

 The APERF, MPERF MSRs are defined to count non-halted cycles.
 Although it is not guaranteed by the architecture, turbostat assumes
 that they count at TSC rate, which is true on all processors tested to date.

 .SH REFERENCES
 "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
 .fi

 .SH "SEE ALSO"
 msr(4), vmstat(8)
 .PP
 .SH AUTHOR
 .nf
 Written by Len Brown <len.brown@intel.com>
	.TH TURBOSTAT 8
	.SH NAME
	turbostat \- Report processor frequency and idle statistics
	.SH SYNOPSIS
	.ft B
	.B turbostat
	.RB [ Options ]
	.RB command
	.br
	.B turbostat
	.RB [ Options ]
	.RB [ "\-i interval_sec" ]
	.SH DESCRIPTION
	\fBturbostat \fP reports processor topology, frequency,
	idle power-state statistics, temperature and power on modern X86 processors.
	Either \fBcommand\fP is forked and statistics are printed
	upon its completion, or statistics are printed periodically.

	\fBturbostat \fP
	must be run on root, and
	minimally requires that the processor
	supports an "invariant" TSC, plus the APERF and MPERF MSRs.
	Additional information is reported depending on hardware counter support.

	.SS Options
	The \fB-p\fP option limits output to the 1st thread in 1st core of each package.
	.PP
	The \fB-P\fP option limits output to the 1st thread in each Package.
	.PP
	The \fB-S\fP option limits output to a 1-line System Summary for each interval.
	.PP
	The \fB-v\fP option increases verbosity.
	.PP
	The \fB-c MSR#\fP option includes the delta of the specified 32-bit MSR counter.
	.PP
	The \fB-C MSR#\fP option includes the delta of the specified 64-bit MSR counter.
	.PP
	The \fB-m MSR#\fP option includes the the specified 32-bit MSR value.
	.PP
	The \fB-M MSR#\fP option includes the the specified 64-bit MSR value.
	.PP
	The \fB-i interval_sec\fP option prints statistics every \fiinterval_sec\fP seconds.
	The default is 5 seconds.
	.PP
	The \fBcommand\fP parameter forks \fBcommand\fP and upon its exit,
	displays the statistics gathered since it was forked.
	.PP
	.SH FIELD DESCRIPTIONS
	.nf
	\fBpk\fP processor package number.
	\fBcor\fP processor core number.
	\fBCPU\fP Linux CPU (logical processor) number.
	Note that multiple CPUs per core indicate support for Intel(R) Hyper-Threading Technology.
	\fB%c0\fP percent of the interval that the CPU retired instructions.
	\fBGHz\fP average clock rate while the CPU was in c0 state.
	\fBTSC\fP average GHz that the TSC ran during the entire interval.
	\fB%c1, %c3, %c6, %c7\fP show the percentage residency in hardware core idle states.
	\fBCTMP\fP Degrees Celsius reported by the per-core Digital Thermal Sensor.
	\fBPTMP\fP Degrees Celsius reported by the per-package Package Thermal Monitor.
	\fB%pc2, %pc3, %pc6, %pc7\fP percentage residency in hardware package idle states.
	\fBPkg_W\fP Watts consumed by the whole package.
	\fBCor_W\fP Watts consumed by the core part of the package.
	\fBGFX_W\fP Watts consumed by the Graphics part of the package -- available only on client processors.
	\fBRAM_W\fP Watts consumed by the DRAM DIMMS -- available only on server processors.
	\fBPKG_%\fP percent of the interval that RAPL throttling was active on the Package.
	\fBRAM_%\fP percent of the interval that RAPL throttling was active on DRAM.
	.fi
	.PP
	.SH EXAMPLE
	Without any parameters, turbostat prints out counters ever 5 seconds.
	(override interval with "-i sec" option, or specify a command
	for turbostat to fork).

	The first row of statistics is a summary for the entire system.
	For residency % columns, the summary is a weighted average.
	For Temperature columns, the summary is the column maximum.
	For Watts columns, the summary is a system total.
	Subsequent rows show per-CPU statistics.

	.nf
	[root@sandy]# ./turbostat
	cor CPU %c0 GHz TSC %c1 %c3 %c6 %c7 CTMP PTMP %pc2 %pc3 %pc6 %pc7 Pkg_W Cor_W GFX_W
	0.06 0.80 2.29 0.11 0.00 0.00 99.83 47 40 0.26 0.01 0.44 98.78 3.49 0.12 0.14
	0 0 0.07 0.80 2.29 0.07 0.00 0.00 99.86 40 40 0.26 0.01 0.44 98.78 3.49 0.12 0.14
	0 4 0.03 0.80 2.29 0.12
	1 1 0.04 0.80 2.29 0.25 0.01 0.00 99.71 40
	1 5 0.16 0.80 2.29 0.13
	2 2 0.05 0.80 2.29 0.06 0.01 0.00 99.88 40
	2 6 0.03 0.80 2.29 0.08
	3 3 0.05 0.80 2.29 0.08 0.00 0.00 99.87 47
	3 7 0.04 0.84 2.29 0.09
	.fi
	.SH SUMMARY EXAMPLE
	The "-s" option prints the column headers just once,
	and then the one line system summary for each sample interval.

	.nf
	[root@wsm]# turbostat -S
	%c0 GHz TSC %c1 %c3 %c6 CTMP %pc3 %pc6
	1.40 2.81 3.38 10.78 43.47 44.35 42 13.67 2.09
	1.34 2.90 3.38 11.48 58.96 28.23 41 19.89 0.15
	1.55 2.72 3.38 26.73 37.66 34.07 42 2.53 2.80
	1.37 2.83 3.38 16.95 60.05 21.63 42 5.76 0.20
	.fi
	.SH VERBOSE EXAMPLE
	The "-v" option adds verbosity to the output:

	.nf
	[root@ivy]# turbostat -v
	turbostat v3.0 November 23, 2012 - Len Brown <lenb@kernel.org>
	CPUID(0): GenuineIntel 13 CPUID levels; family:model:stepping 0x6:3a:9 (6:58:9)
	CPUID(6): APERF, DTS, PTM, EPB
	RAPL: 851 sec. Joule Counter Range
	cpu0: MSR_NHM_PLATFORM_INFO: 0x81010f0012300
	16 * 100 = 1600 MHz max efficiency
	35 * 100 = 3500 MHz TSC frequency
	cpu0: MSR_NHM_SNB_PKG_CST_CFG_CTL: 0x1e008402 (UNdemote-C3, UNdemote-C1, demote-C3, demote-C1, locked: pkg-cstate-limit=2: pc6-noret)
	cpu0: MSR_NHM_TURBO_RATIO_LIMIT: 0x25262727
	37 * 100 = 3700 MHz max turbo 4 active cores
	38 * 100 = 3800 MHz max turbo 3 active cores
	39 * 100 = 3900 MHz max turbo 2 active cores
	39 * 100 = 3900 MHz max turbo 1 active cores
	cpu0: MSR_IA32_ENERGY_PERF_BIAS: 0x00000006 (balanced)
	cpu0: MSR_RAPL_POWER_UNIT: 0x000a1003 (0.125000 Watts, 0.000015 Joules, 0.000977 sec.)
	cpu0: MSR_PKG_POWER_INFO: 0x01e00268 (77 W TDP, RAPL 60 - 0 W, 0.000000 sec.)
	cpu0: MSR_PKG_POWER_LIMIT: 0x830000148268 (UNlocked)
	cpu0: PKG Limit #1: ENabled (77.000000 Watts, 1.000000 sec, clamp DISabled)
	cpu0: PKG Limit #2: ENabled (96.000000 Watts, 0.000977* sec, clamp DISabled)
	cpu0: MSR_PP0_POLICY: 0
	cpu0: MSR_PP0_POWER_LIMIT: 0x00000000 (UNlocked)
	cpu0: Cores Limit: DISabled (0.000000 Watts, 0.000977 sec, clamp DISabled)
	cpu0: MSR_PP1_POLICY: 0
	cpu0: MSR_PP1_POWER_LIMIT: 0x00000000 (UNlocked)
	cpu0: GFX Limit: DISabled (0.000000 Watts, 0.000977 sec, clamp DISabled)
	cpu0: MSR_IA32_TEMPERATURE_TARGET: 0x00691400 (105 C)
	cpu0: MSR_IA32_PACKAGE_THERM_STATUS: 0x884e0000 (27 C)
	cpu0: MSR_IA32_THERM_STATUS: 0x88560000 (19 C +/- 1)
	cpu1: MSR_IA32_THERM_STATUS: 0x88560000 (19 C +/- 1)
	cpu2: MSR_IA32_THERM_STATUS: 0x88540000 (21 C +/- 1)
	cpu3: MSR_IA32_THERM_STATUS: 0x884e0000 (27 C +/- 1)
	...
	.fi
	The \fBmax efficiency\fP frequency, a.k.a. Low Frequency Mode, is the frequency
	available at the minimum package voltage. The \fBTSC frequency\fP is the nominal
	maximum frequency of the processor if turbo-mode were not available. This frequency
	should be sustainable on all CPUs indefinitely, given nominal power and cooling.
	The remaining rows show what maximum turbo frequency is possible
	depending on the number of idle cores. Note that this information is
	not available on all processors.
	.SH FORK EXAMPLE
	If turbostat is invoked with a command, it will fork that command
	and output the statistics gathered when the command exits.
	eg. Here a cycle soaker is run on 1 CPU (see %c0) for a few seconds
	until ^C while the other CPUs are mostly idle:

	.nf
	[root@x980 lenb]# ./turbostat cat /dev/zero > /dev/null
	^C
	cor CPU %c0 GHz TSC %c1 %c3 %c6 %pc3 %pc6
	8.86 3.61 3.38 15.06 31.19 44.89 0.00 0.00
	0 0 1.46 3.22 3.38 16.84 29.48 52.22 0.00 0.00
	0 6 0.21 3.06 3.38 18.09
	1 2 0.53 3.33 3.38 2.80 46.40 50.27
	1 8 0.89 3.47 3.38 2.44
	2 4 1.36 3.43 3.38 9.04 23.71 65.89
	2 10 0.18 2.86 3.38 10.22
	8 1 0.04 2.87 3.38 99.96 0.01 0.00
	8 7 99.72 3.63 3.38 0.27
	9 3 0.31 3.21 3.38 7.64 56.55 35.50
	9 9 0.08 2.95 3.38 7.88
	10 5 1.42 3.43 3.38 2.14 30.99 65.44
	10 11 0.16 2.88 3.38 3.40
	.fi
	Above the cycle soaker drives cpu7 up its 3.6 GHz turbo limit
	while the other processors are generally in various states of idle.

	Note that cpu1 and cpu7 are HT siblings within core8.
	As cpu7 is very busy, it prevents its sibling, cpu1,
	from entering a c-state deeper than c1.

	Note that turbostat reports average GHz of 3.63, while
	the arithmetic average of the GHz column above is lower.
	This is a weighted average, where the weight is %c0. ie. it is the total number of
	un-halted cycles elapsed per time divided by the number of CPUs.
	.SH SMI COUNTING EXAMPLE
	On Intel Nehalem and newer processors, MSR 0x34 is a System Management Mode Interrupt (SMI) counter.
	This counter is shown by default under the "SMI" column.
	.nf
	[root@x980 ~]# turbostat
	cor CPU %c0 GHz TSC SMI %c1 %c3 %c6 CTMP %pc3 %pc6
	0.11 1.91 3.38 0 1.84 0.26 97.79 29 0.82 83.87
	0 0 0.40 1.63 3.38 0 10.27 0.12 89.20 20 0.82 83.88
	0 6 0.06 1.63 3.38 0 10.61
	1 2 0.37 2.63 3.38 0 0.02 0.10 99.51 22
	1 8 0.01 1.62 3.38 0 0.39
	2 4 0.07 1.62 3.38 0 0.04 0.07 99.82 23
	2 10 0.02 1.62 3.38 0 0.09
	8 1 0.23 1.64 3.38 0 0.10 1.07 98.60 24
	8 7 0.02 1.64 3.38 0 0.31
	9 3 0.03 1.62 3.38 0 0.03 0.05 99.89 29
	9 9 0.02 1.62 3.38 0 0.05
	10 5 0.07 1.62 3.38 0 0.08 0.12 99.73 27
	10 11 0.03 1.62 3.38 0 0.13
	^C
	.fi
	.SH NOTES

	.B "turbostat "
	must be run as root.

	.B "turbostat "
	reads hardware counters, but doesn't write them.
	So it will not interfere with the OS or other programs, including
	multiple invocations of itself.

	\fBturbostat \fP
	may work poorly on Linux-2.6.20 through 2.6.29,
	as \fBacpi-cpufreq \fPperiodically cleared the APERF and MPERF
	in those kernels.

	If the TSC column does not make sense, then
	the other numbers will also make no sense.
	Turbostat is lightweight, and its data collection is not atomic.
	These issues are usually caused by an extremely short measurement
	interval (much less than 1 second), or system activity that prevents
	turbostat from being able to run on all CPUS to quickly collect data.

	The APERF, MPERF MSRs are defined to count non-halted cycles.
	Although it is not guaranteed by the architecture, turbostat assumes
	that they count at TSC rate, which is true on all processors tested to date.

	.SH REFERENCES
	"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
	.fi

	.SH "SEE ALSO"
	msr(4), vmstat(8)
	.PP
	.SH AUTHOR
	.nf
	Written by Len Brown <len.brown@intel.com>