NAME

       pmqtest  -  Start  pairs  of threads and measure the latency of interprocess communication
       with POSIX messages queues

SYNTAX

       pmqtest [-a|-a PROC] [-b USEC] [-d DIST] [-i INTV] [-l loops] [-p PRIO] [-S]  [-t|-t  NUM]
       [-T TO]

DESCRIPTION

       The program pmqtest starts pairs of threads that are synchronized via mq_send/mw_receive()
       and measures the latency between sending and receiving the message.

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
              pmqtest 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, --forcetimeout=TO
              Set  an  artificial  delay  of  the send function to force timeout of the receiver,
              requires the -T option

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

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

       -S, --smp
              Test  mode  for  symmetric  multi-processing,  implies  -a and -t and uses the same
              priority on all threads.

       -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.

       -T, --timeout=TO
              Use mq_timedreceive() instead of mq_receive() and specify timeout TO in seconds.

EXAMPLES

       The following example was running on an 8-way processor:

       # pmqtest -Sp99 -i100 -d0
       #0: ID10047, P99, CPU0, I100; #1: ID10048, P99, CPU0, Cycles 153695
       #2: ID10049, P99, CPU1, I100; #3: ID10050, P99, CPU1, Cycles 154211
       #4: ID10051, P99, CPU2, I100; #5: ID10052, P99, CPU2, Cycles 156823
       #6: ID10053, P99, CPU3, I100; #7: ID10054, P99, CPU3, Cycles 158202
       #8: ID10055, P99, CPU4, I100; #9: ID10056, P99, CPU4, Cycles 153399
       #10: ID10057, P99, CPU5, I100; #11: ID10058, P99, CPU5, Cycles 153992
       #12: ID10059, P99, CPU6, I100; #13: ID10060, P99, CPU6, Cycles 156576
       #14: ID10061, P99, CPU7, I100; #15: ID10062, P99, CPU7, Cycles 157957
       #1 -> #0, Min    1, Cur    8, Avg    5, Max   18
       #3 -> #2, Min    1, Cur    4, Avg    5, Max   18
       #5 -> #4, Min    1, Cur    5, Avg    5, Max   19
       #7 -> #6, Min    1, Cur    4, Avg    4, Max   17
       #9 -> #8, Min    1, Cur    9, Avg    5, Max   18
       #11 -> #10, Min    1, Cur    8, Avg    5, Max   18
       #13 -> #12, Min    1, Cur    4, Avg    5, Max   29
       #15 -> #14, Min    1, Cur    8, Avg    4, Max   17

AUTHORS

       Carsten Emde <C.Emde@osadl.org>

SEE ALSO

       mq_send(3p), mq_receive(3p)

                                               0.1                                     pmqtest(8)