Ubuntu Manpage: svsematest - Start two threads or fork two processes and measure the latency of SYSV

NAME

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

SYNTAX

       svsematest [-a|--affinity NUM] [-b|--breaktrace USEC] [-d|--distance DIST]  [-D|--duration
       TIME]   [-f|--fork  [OPT]]  [-i|--interval  INTV]  [--json  FILENAME]  [-l|--loops  LOOPS]
       [-p|--prio PRIO] [-q|--quiet] [-S|--smp] [-t|--threads [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[=NUM]
Run on processor number NUM. 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

-D, --duration=TIME
Specify a length for the test run.
Append 'm', 'h', or 'd' to specify minutes, hours or days.

-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.

--json=FILENAME
Write final results into FILENAME, JSON formatted.

-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.

-q, --quiet
Print a summary only on exit. Useful for automated tests, where only the summary
output needs to be captured.

-S, --smp
SMP testing: options -a -t and same priority of 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 specified, 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