ptsematest - Start two threads and measure the latency of interprocess
communication with POSIX mutex.
ptsematest [-a|-a PROC] [-b USEC] [-d DIST] [-i INTV] [-l loops] [-p
PRIO] [-t|-t NUM]
The program ptsematest starts two threads that are synchronized via
pthread_mutex_unlock()/pthread_mutex_lock() and measures the latency
between releasing and getting the lock.
Run on procesor number PROC. If PROC is not specified, run on
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.
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
Set the base interval of the thread(s) in microseconds (default
is 1000 us). This sets the interval of the first thread. See
Set the number of loops. The default is 0 (endless). This option
is useful for automated tests with a given number of test
cycles. ptsematest is stopped once the number of timer intervals
has been reached.
Set the priority of the process.
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.
The following example was running on a 4-way processor:
# ptsematest -a -t -p99 -i100 -d25 -l1000000
#0: ID8672, P99, CPU0, I100; #1: ID8673, P99, CPU0, Cycles 1000000
#2: ID8674, P98, CPU1, I125; #3: ID8675, P98, CPU1, Cycles 811035
#4: ID8676, P97, CPU2, I150; #5: ID8677, P97, CPU2, Cycles 668130
#6: ID8678, P96, CPU3, I175; #7: ID8679, P96, CPU3, Cycles 589423
#1 -> #0, Min 1, Cur 1, Avg 2, Max 11
#3 -> #2, Min 1, Cur 2, Avg 2, Max 13
#5 -> #4, Min 1, Cur 4, Avg 3, Max 12
#7 -> #6, Min 1, Cur 4, Avg 2, Max 12
Carsten Emde <C.Emde@osadl.org>