NAME
turbostat - Report processor frequency and idle statistics
SYNOPSIS
turbostat [-v] [-M MSR#] command
turbostat [-v] [-M MSR#] [-i interval_sec]
DESCRIPTION
turbostat reports processor topology, frequency and idle
power state
statistics on modern X86 processors. Either command is
forked and
statistics are printed upon its completion, or statistics
are printed
periodically.
turbostat requires that the processor supports an
"invariant" TSC, plus
the APERF and MPERF MSRs. turbostat will report idle cpu
power state
residency on processors that additionally support C-state
residency
counters.
Options
The -v option increases verbosity.
The -M MSR# option dumps the specified MSR, in addition
to the usual
frequency and idle statistics.
The -i interval_sec option prints statistics every
interval_sec
seconds. The default is 5 seconds.
The command parameter forks command and upon its exit,
displays the
statistics gathered since it was forked.
FIELD DESCRIPTIONS
pkg processor package number.
core processor core number.
CPU Linux CPU (logical processor) number.
%c0 percent of the interval that the CPU retired
instructions.
GHz average clock rate while the CPU was in c0 state.
TSC average GHz that the TSC ran during the entire interval.
%c1, %c3, %c6 show the percentage residency in hardware core
idle states.
%pc3, %pc6 percentage residency in hardware package idle
states.
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 reflect the average for the
entire system.
Subsequent rows show per-CPU statistics.
[root@x980]# ./turbostat
core CPU %c0 GHz TSC %c1 %c3 %c6 %pc3 %pc6
0.04 1.62 3.38 0.11 0.00 99.85 0.00 95.07
0 0 0.04 1.62 3.38 0.06 0.00 99.90 0.00 95.07
0 6 0.02 1.62 3.38 0.08 0.00 99.90 0.00 95.07
1 2 0.10 1.62 3.38 0.29 0.00 99.61 0.00 95.07
1 8 0.11 1.62 3.38 0.28 0.00 99.61 0.00 95.07
2 4 0.01 1.62 3.38 0.01 0.00 99.98 0.00 95.07
2 10 0.01 1.61 3.38 0.02 0.00 99.98 0.00 95.07
8 1 0.07 1.62 3.38 0.15 0.00 99.78 0.00 95.07
8 7 0.03 1.62 3.38 0.19 0.00 99.78 0.00 95.07
9 3 0.01 1.62 3.38 0.02 0.00 99.98 0.00 95.07
9 9 0.01 1.62 3.38 0.02 0.00 99.98 0.00 95.07
10 5 0.01 1.62 3.38 0.13 0.00 99.86 0.00 95.07
10 11 0.08 1.62 3.38 0.05 0.00 99.86 0.00 95.07
VERBOSE EXAMPLE
The "-v" option adds verbosity to the output:
GenuineIntel 11 CPUID levels; family:model:stepping 0x6:2c:2
(6:44:2)
12 * 133 = 1600 MHz max efficiency
25 * 133 = 3333 MHz TSC frequency
26 * 133 = 3467 MHz max turbo 4 active cores
26 * 133 = 3467 MHz max turbo 3 active cores
27 * 133 = 3600 MHz max turbo 2 active cores
27 * 133 = 3600 MHz max turbo 1 active cores
The max efficiency frequency, a.k.a. Low Frequency
Mode, is the
frequency available at the minimum package voltage. The TSC
frequency
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.
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:
[root@x980 lenb]# ./turbostat cat /dev/zero > /dev/null
^Ccore CPU %c0 GHz TSC %c1 %c3 %c6 %pc3
%pc6
8.49 3.63 3.38 16.23 0.66 74.63 0.00 0.00
0 0 1.22 3.62 3.38 32.18 0.00 66.60 0.00 0.00
0 6 0.40 3.61 3.38 33.00 0.00 66.60 0.00 0.00
1 2 0.11 3.14 3.38 0.19 3.95 95.75 0.00 0.00
1 8 0.05 2.88 3.38 0.25 3.95 95.75 0.00 0.00
2 4 0.00 3.13 3.38 0.02 0.00 99.98 0.00 0.00
2 10 0.00 3.09 3.38 0.02 0.00 99.98 0.00 0.00
8 1 0.04 3.50 3.38 14.43 0.00 85.54 0.00 0.00
8 7 0.03 2.98 3.38 14.43 0.00 85.54 0.00 0.00
9 3 0.00 3.16 3.38 100.00 0.00 0.00 0.00 0.00
9 9 99.93 3.63 3.38 0.06 0.00 0.00 0.00 0.00
10 5 0.01 2.82 3.38 0.08 0.00 99.91 0.00 0.00
10 11 0.02 3.36 3.38 0.06 0.00 99.91 0.00 0.00
6.950866 sec
Above the cycle soaker drives cpu9 up 3.6 Ghz turbo
limit while the
other processors are generally in various states of idle.
Note that cpu3 is an HT sibling sharing core9 with cpu9, and
thus it is
unable to get to an idle state deeper than c1 while cpu9 is
busy.
Note that turbostat reports average GHz of 3.61, while the
arithmetic
average of the GHz column above is 3.24. 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.
NOTES
turbostat must be run as root.
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.
turbostat may work poorly on Linux-2.6.20 through 2.6.29,
as acpi-
cpufreq periodically cleared the APERF and MPERF in those
kernels.
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.
REFERENCES
"Intel(R) Turbo Boost Technology in Intel(R) Coretm
Microarchitecture
(Nehalem) Based
Processors"
"Intel(R) 64 and IA-32 Architectures Software Developer's
Manual Volume
3B: System Programming
Guide"
FILES
/dev/cpu/*/msr
SEE ALSO
msr(4), vmstat(8)
AUTHORS
Written by Len Brown
