NAME

       sigwaittest  -  Start  two  threads  or fork two processes and measure the latency between
       sending and receiving a signal

SYNTAX

       sigwaittest   [-a|--affinity   PROC]   [-b|--breaktrace   USEC]    [-d|--distance    DIST]
       [-D|--duration  TIME] [-f|--fork [OPT]] [-i|--interval INTV] [--json FILENAME] [-l|--loops
       LOOPS] [-p|--prio PRIO] [-t|--threads [NUM]]

DESCRIPTION

       The program sigwaittest starts two threads or, optionally, forks two  processes  that  are
       synchronized  via  signals and measures the latency between sending a signal and returning
       from sigwait().

OPTIONS

       -a, --affinity[=PROC]
              Run on processor number PROC. If PROC is not specified, run on current processor.

       -b, --breaktrace=USEC
              Send break trace command when latency > USEC. This is a debugging option to control
              the  latency  tracer  in the realtime preemption patch.  It is useful to track down
              unexpected large latencies of a system.

       -d, --distance=DIST
              Set the distance of thread intervals in microseconds  (default  is  500  us).  When
              cyclictest  is  called with the -t option and more than one thread is created, then
              this distance value is added to the interval of the threads: Interval(thread  N)  =
              Interval(thread N-1) + DIST

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

       -f, --fork[=OPT]
              Instead of creating threads (which is the default), fork new processes

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

       --json=FILENAME
              Write final results into FILENAME, JSON formatted.

       -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. sigwaittest is stopped once the
              number of timer intervals has been reached.

       -p, --prio=PRIO
              Set the priority of the process.

       -t, --threads[=NUM]
              Set the number of test threads (default is 1, if this option is not given). If  NUM
              is  specified,  create NUM test threads. If NUM is not specified, NUM is set to the
              number of available CPUs.

EXAMPLES

       The following example was running on a 4-way CPU:

       # sigwaittest -a -t -p99 -i100 -d25 -l1000000
       #0: ID11510, P99, CPU0, I100; #1: ID11511, P99, CPU0, Cycles 1000000
       #2: ID11512, P98, CPU1, I125; #3: ID11513, P98, CPU1, Cycles 817484
       #4: ID11514, P97, CPU2, I150; #5: ID11515, P97, CPU2, Cycles 668213
       #6: ID11516, P96, CPU3, I175; #7: ID11517, P96, CPU3, Cycles 597344
       #1 -> #0, Min    1, Cur    2, Avg    3, Max   30
       #3 -> #2, Min    1, Cur   26, Avg    3, Max   42
       #5 -> #4, Min    1, Cur   46, Avg    4, Max   67
       #7 -> #6, Min    1, Cur    2, Avg    3, Max   74

AUTHORS

       Carsten Emde <C.Emde@osadl.org>

SEE ALSO

       kill(2), sigwait(3)

                                               0.1                                 sigwaittest(8)