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)