tools/power/x86/turbostat/turbostat.8

   1 .TH TURBOSTAT 8
   2 .SH NAME
   3 turbostat \- Report processor frequency and idle statistics
   4 .SH SYNOPSIS
   5 .ft B
   6 .B turbostat
   7 .RB [ "\-s" ]
   8 .RB [ "\-v" ]
   9 .RB [ "\-M MSR#" ]
  10 .RB command
  11 .br
  12 .B turbostat
  13 .RB [ "\-s" ]
  14 .RB [ "\-v" ]
  15 .RB [ "\-M MSR#" ]
  16 .RB [ "\-i interval_sec" ]
  17 .SH DESCRIPTION
  18 \fBturbostat \fP reports processor topology, frequency
  19 and idle power state statistics on modern X86 processors.
  20 Either \fBcommand\fP is forked and statistics are printed
  21 upon its completion, or statistics are printed periodically.
  22
  23 \fBturbostat \fP
  24 requires that the processor
  25 supports an "invariant" TSC, plus the APERF and MPERF MSRs.
  26 \fBturbostat \fP will report idle cpu power state residency
  27 on processors that additionally support C-state residency counters.
  28
  29 .SS Options
  30 The \fB-s\fP option prints only a 1-line summary for each sample interval.
  31 .PP
  32 The \fB-v\fP option increases verbosity.
  33 .PP
  34 The \fB-M MSR#\fP option dumps the specified MSR,
  35 in addition to the usual frequency and idle statistics.
  36 .PP
  37 The \fB-i interval_sec\fP option prints statistics every \fiinterval_sec\fP seconds.
  38 The default is 5 seconds.
  39 .PP
  40 The \fBcommand\fP parameter forks \fBcommand\fP and upon its exit,
  41 displays the statistics gathered since it was forked.
  42 .PP
  43 .SH FIELD DESCRIPTIONS
  44 .nf
  45 \fBpk\fP processor package number.
  46 \fBcor\fP processor core number.
  47 \fBCPU\fP Linux CPU (logical processor) number.
  48 Note that multiple CPUs per core indicate support for Intel(R) Hyper-Threading Technology.
  49 \fB%c0\fP percent of the interval that the CPU retired instructions.
  50 \fBGHz\fP average clock rate while the CPU was in c0 state.
  51 \fBTSC\fP average GHz that the TSC ran during the entire interval.
  52 \fB%c1, %c3, %c6, %c7\fP show the percentage residency in hardware core idle states.
  53 \fB%pc2, %pc3, %pc6, %pc7\fP percentage residency in hardware package idle states.
  54 .fi
  55 .PP
  56 .SH EXAMPLE
  57 Without any parameters, turbostat prints out counters ever 5 seconds.
  58 (override interval with "-i sec" option, or specify a command
  59 for turbostat to fork).
  60
  61 The first row of statistics is a summary for the entire system.
  62 Note that the summary is a weighted average.
  63 Subsequent rows show per-CPU statistics.
  64
  65 .nf
  66 [root@x980]# ./turbostat
  67 cor CPU    %c0  GHz  TSC    %c1    %c3    %c6   %pc3   %pc6
  68           0.60 1.63 3.38   2.91   0.00  96.49   0.00  76.64
  69   0   0   0.59 1.62 3.38   4.51   0.00  94.90   0.00  76.64
  70   0   6   1.13 1.64 3.38   3.97   0.00  94.90   0.00  76.64
  71   1   2   0.08 1.62 3.38   0.07   0.00  99.85   0.00  76.64
  72   1   8   0.03 1.62 3.38   0.12   0.00  99.85   0.00  76.64
  73   2   4   0.01 1.62 3.38   0.06   0.00  99.93   0.00  76.64
  74   2  10   0.04 1.62 3.38   0.02   0.00  99.93   0.00  76.64
  75   8   1   2.85 1.62 3.38  11.71   0.00  85.44   0.00  76.64
  76   8   7   1.98 1.62 3.38  12.58   0.00  85.44   0.00  76.64
  77   9   3   0.36 1.62 3.38   0.71   0.00  98.93   0.00  76.64
  78   9   9   0.09 1.62 3.38   0.98   0.00  98.93   0.00  76.64
  79  10   5   0.03 1.62 3.38   0.09   0.00  99.87   0.00  76.64
  80  10  11   0.07 1.62 3.38   0.06   0.00  99.87   0.00  76.64
  81 .fi
  82 .SH SUMMARY EXAMPLE
  83 The "-s" option prints the column headers just once,
  84 and then the one line system summary for each sample interval.
  85
  86 .nf
  87 [root@x980]# ./turbostat -s
  88    %c0  GHz  TSC    %c1    %c3    %c6   %pc3   %pc6
  89   0.61 1.89 3.38   5.95   0.00  93.44   0.00  66.33
  90   0.52 1.62 3.38   6.83   0.00  92.65   0.00  61.11
  91   0.62 1.92 3.38   5.47   0.00  93.91   0.00  67.31
  92 .fi
  93 .SH VERBOSE EXAMPLE
  94 The "-v" option adds verbosity to the output:
  95
  96 .nf
  97 GenuineIntel 11 CPUID levels; family:model:stepping 0x6:2c:2 (6:44:2)
  98 12 * 133 = 1600 MHz max efficiency
  99 25 * 133 = 3333 MHz TSC frequency
 100 26 * 133 = 3467 MHz max turbo 4 active cores
 101 26 * 133 = 3467 MHz max turbo 3 active cores
 102 27 * 133 = 3600 MHz max turbo 2 active cores
 103 27 * 133 = 3600 MHz max turbo 1 active cores
 104
 105 .fi
 106 The \fBmax efficiency\fP frequency, a.k.a. Low Frequency Mode, is the frequency
 107 available at the minimum package voltage.  The \fBTSC frequency\fP is the nominal
 108 maximum frequency of the processor if turbo-mode were not available.  This frequency
 109 should be sustainable on all CPUs indefinitely, given nominal power and cooling.
 110 The remaining rows show what maximum turbo frequency is possible
 111 depending on the number of idle cores.  Note that this information is
 112 not available on all processors.
 113 .SH FORK EXAMPLE
 114 If turbostat is invoked with a command, it will fork that command
 115 and output the statistics gathered when the command exits.
 116 eg. Here a cycle soaker is run on 1 CPU (see %c0) for a few seconds
 117 until ^C while the other CPUs are mostly idle:
 118
 119 .nf
 120 [root@x980 lenb]# ./turbostat cat /dev/zero > /dev/null
 121 ^C
 122 cor CPU    %c0  GHz  TSC    %c1    %c3    %c6   %pc3   %pc6
 123           8.63 3.64 3.38  14.46   0.49  76.42   0.00   0.00
 124   0   0   0.34 3.36 3.38  99.66   0.00   0.00   0.00   0.00
 125   0   6  99.96 3.64 3.38   0.04   0.00   0.00   0.00   0.00
 126   1   2   0.14 3.50 3.38   1.75   2.04  96.07   0.00   0.00
 127   1   8   0.38 3.57 3.38   1.51   2.04  96.07   0.00   0.00
 128   2   4   0.01 2.65 3.38   0.06   0.00  99.93   0.00   0.00
 129   2  10   0.03 2.12 3.38   0.04   0.00  99.93   0.00   0.00
 130   8   1   0.91 3.59 3.38  35.27   0.92  62.90   0.00   0.00
 131   8   7   1.61 3.63 3.38  34.57   0.92  62.90   0.00   0.00
 132   9   3   0.04 3.38 3.38   0.20   0.00  99.76   0.00   0.00
 133   9   9   0.04 3.29 3.38   0.20   0.00  99.76   0.00   0.00
 134  10   5   0.03 3.08 3.38   0.12   0.00  99.85   0.00   0.00
 135  10  11   0.05 3.07 3.38   0.10   0.00  99.85   0.00   0.00
 136 4.907015 sec
 137
 138 .fi
 139 Above the cycle soaker drives cpu6 up 3.6 Ghz turbo limit
 140 while the other processors are generally in various states of idle.
 141
 142 Note that cpu0 is an HT sibling sharing core0
 143 with cpu6, and thus it is unable to get to an idle state
 144 deeper than c1 while cpu6 is busy.
 145
 146 Note that turbostat reports average GHz of 3.64, while
 147 the arithmetic average of the GHz column above is lower.
 148 This is a weighted average, where the weight is %c0.  ie. it is the total number of
 149 un-halted cycles elapsed per time divided by the number of CPUs.
 150 .SH NOTES
 151
 152 .B "turbostat "
 153 must be run as root.
 154
 155 .B "turbostat "
 156 reads hardware counters, but doesn't write them.
 157 So it will not interfere with the OS or other programs, including
 158 multiple invocations of itself.
 159
 160 \fBturbostat \fP
 161 may work poorly on Linux-2.6.20 through 2.6.29,
 162 as \fBacpi-cpufreq \fPperiodically cleared the APERF and MPERF
 163 in those kernels.
 164
 165 The APERF, MPERF MSRs are defined to count non-halted cycles.
 166 Although it is not guaranteed by the architecture, turbostat assumes
 167 that they count at TSC rate, which is true on all processors tested to date.
 168
 169 .SH REFERENCES
 170 "Intel® Turbo Boost Technology
 171 in Intel® Core™ Microarchitecture (Nehalem) Based Processors"
 172 http://download.intel.com/design/processor/applnots/320354.pdf
 173
 174 "Intel® 64 and IA-32 Architectures Software Developer's Manual
 175 Volume 3B: System Programming Guide"
 176 http://www.intel.com/products/processor/manuals/
 177
 178 .SH FILES
 179 .ta
 180 .nf
 181 /dev/cpu/*/msr
 182 .fi
 183
 184 .SH "SEE ALSO"
 185 msr(4), vmstat(8)
 186 .PP
 187 .SH AUTHOR
 188 .nf
 189 Written by Len Brown <len.brown@intel.com>