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172 lines
6.3 KiB
172 lines
6.3 KiB
.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 [ "\-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 [ "\-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-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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\fBpkg\fP processor package number.
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\fBcore\fP processor core number.
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\fBCPU\fP Linux CPU (logical processor) number.
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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\fP show the percentage residency in hardware core idle states.
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\fB%pc3, %pc6\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 reflect the average for the entire system.
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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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core CPU %c0 GHz TSC %c1 %c3 %c6 %pc3 %pc6
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0.04 1.62 3.38 0.11 0.00 99.85 0.00 95.07
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0 0 0.04 1.62 3.38 0.06 0.00 99.90 0.00 95.07
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0 6 0.02 1.62 3.38 0.08 0.00 99.90 0.00 95.07
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1 2 0.10 1.62 3.38 0.29 0.00 99.61 0.00 95.07
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1 8 0.11 1.62 3.38 0.28 0.00 99.61 0.00 95.07
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2 4 0.01 1.62 3.38 0.01 0.00 99.98 0.00 95.07
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2 10 0.01 1.61 3.38 0.02 0.00 99.98 0.00 95.07
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8 1 0.07 1.62 3.38 0.15 0.00 99.78 0.00 95.07
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8 7 0.03 1.62 3.38 0.19 0.00 99.78 0.00 95.07
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9 3 0.01 1.62 3.38 0.02 0.00 99.98 0.00 95.07
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9 9 0.01 1.62 3.38 0.02 0.00 99.98 0.00 95.07
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10 5 0.01 1.62 3.38 0.13 0.00 99.86 0.00 95.07
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10 11 0.08 1.62 3.38 0.05 0.00 99.86 0.00 95.07
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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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^Ccore CPU %c0 GHz TSC %c1 %c3 %c6 %pc3 %pc6
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8.49 3.63 3.38 16.23 0.66 74.63 0.00 0.00
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0 0 1.22 3.62 3.38 32.18 0.00 66.60 0.00 0.00
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0 6 0.40 3.61 3.38 33.00 0.00 66.60 0.00 0.00
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1 2 0.11 3.14 3.38 0.19 3.95 95.75 0.00 0.00
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1 8 0.05 2.88 3.38 0.25 3.95 95.75 0.00 0.00
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2 4 0.00 3.13 3.38 0.02 0.00 99.98 0.00 0.00
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2 10 0.00 3.09 3.38 0.02 0.00 99.98 0.00 0.00
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8 1 0.04 3.50 3.38 14.43 0.00 85.54 0.00 0.00
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8 7 0.03 2.98 3.38 14.43 0.00 85.54 0.00 0.00
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9 3 0.00 3.16 3.38 100.00 0.00 0.00 0.00 0.00
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9 9 99.93 3.63 3.38 0.06 0.00 0.00 0.00 0.00
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10 5 0.01 2.82 3.38 0.08 0.00 99.91 0.00 0.00
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10 11 0.02 3.36 3.38 0.06 0.00 99.91 0.00 0.00
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6.950866 sec
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.fi
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Above the cycle soaker drives cpu9 up 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 cpu3 is an HT sibling sharing core9
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with cpu9, and thus it is unable to get to an idle state
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deeper than c1 while cpu9 is busy.
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Note that turbostat reports average GHz of 3.61, while
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the arithmetic average of the GHz column above is 3.24.
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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 AUTHORS
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.nf
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Written by Len Brown <len.brown@intel.com>
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