forked from Minki/linux
c98d5d9444
Measuring large profoundly-idle configurations requires turbostat to be more lightweight. Otherwise, the operation of turbostat itself can interfere with the measurements. This re-write makes turbostat topology aware. Hardware is accessed in "topology order". Redundant hardware accesses are deleted. Redundant output is deleted. Also, output is buffered and local RDTSC use replaces remote MSR access for TSC. From a feature point of view, the output looks different since redundant figures are absent. Also, there are now -c and -p options -- to restrict output to the 1st thread in each core, and the 1st thread in each package, respectively. This is helpful to reduce output on big systems, where more detail than the "-s" system summary is desired. Finally, periodic mode output is now on stdout, not stderr. Turbostat v2 is also slightly more robust in handling run-time CPU online/offline events, as it now checks the actual map of on-line cpus rather than just the total number of on-line cpus. Signed-off-by: Len Brown <len.brown@intel.com>
193 lines
6.6 KiB
Groff
193 lines
6.6 KiB
Groff
.TH TURBOSTAT 8
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.SH NAME
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turbostat \- Report processor frequency and idle statistics
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.SH SYNOPSIS
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.ft B
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.B turbostat
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.RB [ "\-s" ]
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.RB [ "\-v" ]
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.RB [ "\-M MSR#" ]
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.RB command
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.br
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.B turbostat
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.RB [ "\-s" ]
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.RB [ "\-v" ]
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.RB [ "\-M MSR#" ]
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.RB [ "\-i interval_sec" ]
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.SH DESCRIPTION
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\fBturbostat \fP reports processor topology, frequency
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and idle power state statistics on modern X86 processors.
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Either \fBcommand\fP is forked and statistics are printed
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upon its completion, or statistics are printed periodically.
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\fBturbostat \fP
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requires that the processor
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supports an "invariant" TSC, plus the APERF and MPERF MSRs.
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\fBturbostat \fP will report idle cpu power state residency
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on processors that additionally support C-state residency counters.
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.SS Options
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The \fB-s\fP option limits output to a 1-line system summary for each interval.
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.PP
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The \fB-c\fP option limits output to the 1st thread in each core.
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.PP
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The \fB-p\fP option limits output to the 1st thread in each package.
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.PP
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The \fB-v\fP option increases verbosity.
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.PP
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The \fB-M MSR#\fP option dumps the specified MSR,
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in addition to the usual frequency and idle statistics.
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.PP
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The \fB-i interval_sec\fP option prints statistics every \fiinterval_sec\fP seconds.
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The default is 5 seconds.
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.PP
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The \fBcommand\fP parameter forks \fBcommand\fP and upon its exit,
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displays the statistics gathered since it was forked.
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.PP
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.SH FIELD DESCRIPTIONS
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.nf
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\fBpk\fP processor package number.
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\fBcor\fP processor core number.
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\fBCPU\fP Linux CPU (logical processor) number.
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Note that multiple CPUs per core indicate support for Intel(R) Hyper-Threading Technology.
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\fB%c0\fP percent of the interval that the CPU retired instructions.
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\fBGHz\fP average clock rate while the CPU was in c0 state.
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\fBTSC\fP average GHz that the TSC ran during the entire interval.
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\fB%c1, %c3, %c6, %c7\fP show the percentage residency in hardware core idle states.
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\fB%pc2, %pc3, %pc6, %pc7\fP percentage residency in hardware package idle states.
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.fi
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.PP
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.SH EXAMPLE
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Without any parameters, turbostat prints out counters ever 5 seconds.
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(override interval with "-i sec" option, or specify a command
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for turbostat to fork).
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The first row of statistics is a summary for the entire system.
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Note that the summary is a weighted average.
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Subsequent rows show per-CPU statistics.
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.nf
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[root@x980]# ./turbostat
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cor CPU %c0 GHz TSC %c1 %c3 %c6 %pc3 %pc6
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0.09 1.62 3.38 1.83 0.32 97.76 1.26 83.61
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0 0 0.15 1.62 3.38 10.23 0.05 89.56 1.26 83.61
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0 6 0.05 1.62 3.38 10.34
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1 2 0.03 1.62 3.38 0.07 0.05 99.86
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1 8 0.03 1.62 3.38 0.06
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2 4 0.21 1.62 3.38 0.10 1.49 98.21
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2 10 0.02 1.62 3.38 0.29
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8 1 0.04 1.62 3.38 0.04 0.08 99.84
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8 7 0.01 1.62 3.38 0.06
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9 3 0.53 1.62 3.38 0.10 0.20 99.17
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9 9 0.02 1.62 3.38 0.60
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10 5 0.01 1.62 3.38 0.02 0.04 99.92
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10 11 0.02 1.62 3.38 0.02
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.fi
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.SH SUMMARY EXAMPLE
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The "-s" option prints the column headers just once,
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and then the one line system summary for each sample interval.
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.nf
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[root@x980]# ./turbostat -s
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%c0 GHz TSC %c1 %c3 %c6 %pc3 %pc6
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0.23 1.67 3.38 2.00 0.30 97.47 1.07 82.12
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0.10 1.62 3.38 1.87 2.25 95.77 12.02 72.60
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0.20 1.64 3.38 1.98 0.11 97.72 0.30 83.36
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0.11 1.70 3.38 1.86 1.81 96.22 9.71 74.90
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.fi
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.SH VERBOSE EXAMPLE
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The "-v" option adds verbosity to the output:
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.nf
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GenuineIntel 11 CPUID levels; family:model:stepping 0x6:2c:2 (6:44:2)
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12 * 133 = 1600 MHz max efficiency
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25 * 133 = 3333 MHz TSC frequency
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26 * 133 = 3467 MHz max turbo 4 active cores
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26 * 133 = 3467 MHz max turbo 3 active cores
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27 * 133 = 3600 MHz max turbo 2 active cores
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27 * 133 = 3600 MHz max turbo 1 active cores
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.fi
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The \fBmax efficiency\fP frequency, a.k.a. Low Frequency Mode, is the frequency
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available at the minimum package voltage. The \fBTSC frequency\fP is the nominal
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maximum frequency of the processor if turbo-mode were not available. This frequency
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should be sustainable on all CPUs indefinitely, given nominal power and cooling.
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The remaining rows show what maximum turbo frequency is possible
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depending on the number of idle cores. Note that this information is
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not available on all processors.
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.SH FORK EXAMPLE
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If turbostat is invoked with a command, it will fork that command
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and output the statistics gathered when the command exits.
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eg. Here a cycle soaker is run on 1 CPU (see %c0) for a few seconds
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until ^C while the other CPUs are mostly idle:
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.nf
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[root@x980 lenb]# ./turbostat cat /dev/zero > /dev/null
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^C
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cor CPU %c0 GHz TSC %c1 %c3 %c6 %pc3 %pc6
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8.86 3.61 3.38 15.06 31.19 44.89 0.00 0.00
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0 0 1.46 3.22 3.38 16.84 29.48 52.22 0.00 0.00
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0 6 0.21 3.06 3.38 18.09
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1 2 0.53 3.33 3.38 2.80 46.40 50.27
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1 8 0.89 3.47 3.38 2.44
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2 4 1.36 3.43 3.38 9.04 23.71 65.89
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2 10 0.18 2.86 3.38 10.22
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8 1 0.04 2.87 3.38 99.96 0.01 0.00
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8 7 99.72 3.63 3.38 0.27
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9 3 0.31 3.21 3.38 7.64 56.55 35.50
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9 9 0.08 2.95 3.38 7.88
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10 5 1.42 3.43 3.38 2.14 30.99 65.44
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10 11 0.16 2.88 3.38 3.40
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.fi
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Above the cycle soaker drives cpu7 up its 3.6 Ghz turbo limit
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while the other processors are generally in various states of idle.
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Note that cpu1 and cpu7 are HT siblings within core8.
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As cpu7 is very busy, it prevents its sibling, cpu1,
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from entering a c-state deeper than c1.
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Note that turbostat reports average GHz of 3.63, while
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the arithmetic average of the GHz column above is lower.
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This is a weighted average, where the weight is %c0. ie. it is the total number of
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un-halted cycles elapsed per time divided by the number of CPUs.
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.SH NOTES
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.B "turbostat "
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must be run as root.
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.B "turbostat "
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reads hardware counters, but doesn't write them.
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So it will not interfere with the OS or other programs, including
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multiple invocations of itself.
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\fBturbostat \fP
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may work poorly on Linux-2.6.20 through 2.6.29,
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as \fBacpi-cpufreq \fPperiodically cleared the APERF and MPERF
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in those kernels.
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The APERF, MPERF MSRs are defined to count non-halted cycles.
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Although it is not guaranteed by the architecture, turbostat assumes
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that they count at TSC rate, which is true on all processors tested to date.
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.SH REFERENCES
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"Intel® Turbo Boost Technology
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in Intel® Core™ Microarchitecture (Nehalem) Based Processors"
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http://download.intel.com/design/processor/applnots/320354.pdf
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"Intel® 64 and IA-32 Architectures Software Developer's Manual
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Volume 3B: System Programming Guide"
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http://www.intel.com/products/processor/manuals/
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.SH FILES
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.ta
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.nf
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/dev/cpu/*/msr
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.fi
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.SH "SEE ALSO"
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msr(4), vmstat(8)
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.PP
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.SH AUTHOR
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.nf
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Written by Len Brown <len.brown@intel.com>
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