NAME

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

SYNTAX

       sigwaittest [-a|-a PROC] [-b USEC] [-d DIST] [-f] [-i INTV] [-l loops] [-p PRIO] [-t|-t 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

       -f, --fork
              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.

       -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)