svsematest(8)															     svsematest(8)

NAME

       svsematest - Start two threads or fork two processes and measure the latency of SYSV semaphores

SYNTAX

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

DESCRIPTION

       The  program  svsematest  starts two threads or, optionally, forks two processes that are synchronized via SYSV semaphores and measures the
       latency between releasing a semaphore on one side and getting it on the other side.

OPTIONS

       -a, --affinity[=PROC]
	      Run on procesor 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  cylictest 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.
	      svsematest 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 specifed, NUM is set to the number of available CPUs.

EXAMPLES

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

       # svsematest -a -t -p99 -i100 -d25 -l1000000
       #0: ID13110, P99, CPU0, I100; #1: ID13111, P99, CPU0, Cycles 1000000
       #2: ID13112, P98, CPU1, I125; #3: ID13113, P98, CPU1, Cycles 813573
       #4: ID13114, P97, CPU2, I150; #5: ID13115, P97, CPU2, Cycles 667285
       #6: ID13116, P96, CPU3, I175; #7: ID13117, P96, CPU3, Cycles 591403
       #1 -> #0, Min	1, Cur	  2, Avg    2, Max   12
       #3 -> #2, Min	1, Cur	  3, Avg    2, Max   12
       #5 -> #4, Min	1, Cur	  3, Avg    3, Max   12
       #7 -> #6, Min	1, Cur	  2, Avg    3, Max   11

AUTHORS

       Carsten Emde <C.Emde@osadl.org>

SEE ALSO

       semop(2)

									0.1							     svsematest(8)