Provided by: rt-tests_1.0-3_amd64 bug


       cyclictest - High resolution test program


       cyclictest  [  -hfmnqrsvMS  ] [-a proc ] [-A align ] [-b usec ] [-c clock ] [-d dist ] [-h
       histogram ] [-i intv ] [-l loop ] [-o red ] [-p prio ] [-t num ] [-D time] [-w]  [-W]  [-y
       policy ] [ -S | -U ]


       These  programs  follow the usual GNU command line syntax, with long options starting with
       two dashes ('--').
       A summary of options is included below.

       -a, --affinity[=PROC-SET]
              Run threads on the set of  processors  given  by  PROC-SET.   If  PROC-SET  is  not
              specified,  all processors will be used.  Threads will be assigned to processors in
              the set in numeric order, in a round-robin fashion.
              The set of processors can be specified as A,B,C, or A-C, or A-B,D-F,  and  so  on*.
              The  !  character  can be used to negate a set.  For example, !B-D means to use all
              available CPUs except B through D.  The cpu numbers are the same as  shown  in  the
              processor  field  in /proc/cpuinfo.  See numa(3) for more information on specifying
              CPU sets.  * Support for CPU sets requires libnuma version >= 2.  For  libnuma  v1,
              PROC-SET, if specified, must be a single CPU number.

       -A, --align=USEC
              Align thread wakeups to a specific offset in microseconds

       -b, --breaktrace=USEC
              Send break trace command when latency > USEC

       -B, --preemptirqs
              Both preempt and irqsoff tracing (used with -b)

       -c, --clock=CLOCK
              select clock
              0 = CLOCK_MONOTONIC (default)
              1 = CLOCK_REALTIME

       -C, --context
              context switch tracing (used with -b)

       -d, --distance=DIST
              Distance of thread intervals in us, default = 500

       -D, --duration=TIME
              Specify a length for the test run.
              Append 'm', 'h', or 'd' to specify minutes, hours or days.

       -E, --event
              event tracing (used with -b)

       -f, --ftrace
              Enable  function tracing using ftrace as tracer. This option is available only with

       -F, --fifo=<path>
              Create a named pipe at path and write stats to it

       -h, --histogram=US
              Dump latency histogram to stdout after the run. US is the max latency time to be be
              tracked in microseconds. This option runs all threads at the same priority.

       -H, --histofall=MAXLATENCYINUS
              Same  as  -h  except  that an additional histogram column is displayed at the right
              that contains summary data of all thread histograms. If cyclictest  runs  a  single
              thread only, the -H option is equivalent to -h.

              Dump the latency histogram to <path> instead of stdout.

       -i, --interval=INTV
              Set  the  base  interval of the thread(s) in microseconds (default is 1000us). This
              sets the interval of the first thread. See also -d.

       -I, --irqsoff
              Irgsoff tracing (used with -b)

       -l, --loops=LOOPS
              Set the number of loops. The default is 0 (endless).  This  option  is  useful  for
              automated  tests with a given number of test cycles. Cyclictest is stopped once the
              number of timer intervals has been reached.

              Save battery when running cyclictest. This will give you poorer  realtime  results,
              but will not drain your battery so quickly.

       -m, --mlockall
              Lock current and future memory allocations to prevent being paged out

       -M, --refresh_on_max
              Delay  updating  the  screen  until  a  new max latency is hit. (useful for running
              cyclictest on low-bandwidth connections)

       -n, --nanosleep
              Use clock_nanosleep instead of posix interval timers. Setting this option runs  the
              tests with clock_nanosleep instead of posix interval timers.

              suppress tracing

       -N, --nsecs
              Show results in nanoseconds instead of microseconds, which is the default unit.

       -o, --oscope=RED
              Oscilloscope mode, reduce verbose output by RED.

       -O, --traceopt=TRACING_OPTION
              Used  to  pass tracing options to ftrace tracers. May be invoked multiple times for
              multiple    trace    options.    For    example    trace    options     look     at

       -p, --prio=PRIO
              Set  the  priority of the first thread. The given priority is set to the first test
              thread.  Each  further  thread  gets  a  lower  priority:  Priority(Thread   N)   =
              max(Priority(Thread N-1) - 1, 0)

       -P, --preemptoff
              Preempt off tracing (used with -b)

              set  the  scheduler  policy of the measurement threads where NAME is one of: other,
              normal, batch, idle, fifo, rr

              spread priority levels starting at a specified value

       -q, --quiet
              Print a summary only on exit. Useful for automated tests, where  only  the  summary
              output needs to be captured.

       -r, --relative
              Use  relative  timers instead of absolute. The default behaviour of the tests is to
              use absolute timers. This option is there for completeness and should not  be  used
              for reproducible tests.

       -R, --resolution
              Check  clock resolution, calling clock_gettime() many times. List of lock_gettime()
              values will be reported with -X

       --secaligned [USEC]
              align thread wakeups to the next full second and apply the optional offset.

       -s, --system
              Use sys_nanosleep and sys_setitimer instead of posix timers. Note, that -s can only
              be  used  with one thread because itimers are per process and not per thread. -s in
              combination with -n uses the nanosleep syscall and is not restricted to one thread.

       -S, --smp
              Set options for standard testing on SMP systems. Equivalent to using  the  options:
              "-t -a -n" as well keeping any specified priority equal across all threads

              record all spikes > trigger

       --spike-nodes=[num of nodes]
              These are the maximum number of spikes we can record.
              The default is 1024 if not specified.

       --smi  Enable SMI count/detection on processors with SMI count support.

       -t, --threads[=NUM]
              Set  the  number of test threads (default is 1). Create NUM test threads. If NUM is
              not specified, NUM is set to the number of available CPUs. See -d, -i  and  -p  for
              further information.

              write a trace mark when -b latency is exceeded.

       -T, --tracer=TRACEFUNC
              set  the  ftrace tracer function. Used with the -b option. Must be one of the trace
              functions                 available                 from                  <debugfs-

       -u, --unbuffered
              force unbuffered output for live processing

       -U, --numa
              Standard NUMA testing (similar to SMP option) thread data structures allocated from
              local node.

       -v, --verbose
              Output values on stdout for statistics. This option is used to  gather  statistical
              information  about  the  latency  distribution.  The  output is sent to stdout. The
              output format is:


              where n=task number c=count v=latency value in us.

       -w, --wakeup
              task wakeup tracing (used with -b)

       -W, --wakeuprt
              rt-task wakeup tracing (used with -b)

              Print info userful for debugging cyclictest


       numa(3), numactl(8),


       cyclictest was written by Thomas Gleixner <>.

       This manual page was written by Alessio Igor Bogani <>, for  the  Debian
       project (but may be used by others).
       Updated by John Kacur <>

                                          April 22, 2016                            CYCLICTEST(8)