190 lines
6.9 KiB
Groff
190 lines
6.9 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 prints only a 1-line summary for each sample interval.
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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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0.60 1.63 3.38 2.91 0.00 96.49 0.00 76.64
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0 0 0.59 1.62 3.38 4.51 0.00 94.90 0.00 76.64
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0 6 1.13 1.64 3.38 3.97 0.00 94.90 0.00 76.64
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1 2 0.08 1.62 3.38 0.07 0.00 99.85 0.00 76.64
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1 8 0.03 1.62 3.38 0.12 0.00 99.85 0.00 76.64
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2 4 0.01 1.62 3.38 0.06 0.00 99.93 0.00 76.64
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2 10 0.04 1.62 3.38 0.02 0.00 99.93 0.00 76.64
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8 1 2.85 1.62 3.38 11.71 0.00 85.44 0.00 76.64
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8 7 1.98 1.62 3.38 12.58 0.00 85.44 0.00 76.64
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9 3 0.36 1.62 3.38 0.71 0.00 98.93 0.00 76.64
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9 9 0.09 1.62 3.38 0.98 0.00 98.93 0.00 76.64
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10 5 0.03 1.62 3.38 0.09 0.00 99.87 0.00 76.64
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10 11 0.07 1.62 3.38 0.06 0.00 99.87 0.00 76.64
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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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0.61 1.89 3.38 5.95 0.00 93.44 0.00 66.33
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0.52 1.62 3.38 6.83 0.00 92.65 0.00 61.11
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0.62 1.92 3.38 5.47 0.00 93.91 0.00 67.31
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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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8.63 3.64 3.38 14.46 0.49 76.42 0.00 0.00
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0 0 0.34 3.36 3.38 99.66 0.00 0.00 0.00 0.00
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0 6 99.96 3.64 3.38 0.04 0.00 0.00 0.00 0.00
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1 2 0.14 3.50 3.38 1.75 2.04 96.07 0.00 0.00
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1 8 0.38 3.57 3.38 1.51 2.04 96.07 0.00 0.00
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2 4 0.01 2.65 3.38 0.06 0.00 99.93 0.00 0.00
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2 10 0.03 2.12 3.38 0.04 0.00 99.93 0.00 0.00
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8 1 0.91 3.59 3.38 35.27 0.92 62.90 0.00 0.00
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8 7 1.61 3.63 3.38 34.57 0.92 62.90 0.00 0.00
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9 3 0.04 3.38 3.38 0.20 0.00 99.76 0.00 0.00
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9 9 0.04 3.29 3.38 0.20 0.00 99.76 0.00 0.00
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10 5 0.03 3.08 3.38 0.12 0.00 99.85 0.00 0.00
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10 11 0.05 3.07 3.38 0.10 0.00 99.85 0.00 0.00
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4.907015 sec
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.fi
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Above the cycle soaker drives cpu6 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 cpu0 is an HT sibling sharing core0
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with cpu6, and thus it is unable to get to an idle state
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deeper than c1 while cpu6 is busy.
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Note that turbostat reports average GHz of 3.64, 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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