1ptsematest(8) ptsematest(8)
2
6 ptsematest - Start two threads and measure the latency of interprocess
7 communication with POSIX mutex.
8
10 ptsematest [-a|--affinity [PROC]] [-b|--breaktrace USEC] [-d|--distance
11 DIST] [-D|--duration TIME] [-h|--help] [-i|--interval INTV] [--json
12 FILENAME] [-l|--loops LOOPS] [-p|--prio PRIO] [-q|--quiet] [-S|--smp]
13 [-t|--threads [NUM]]
14
16 The program ptsematest starts two threads that are synchronized via
17 pthread_mutex_unlock()/pthread_mutex_lock() and measures the latency
18 between releasing and getting the lock.
19
21 -a, --affinity[=PROC]
22 Run on processor number PROC. If PROC is not specified, run on
23 current processor.
24 -b, --breaktrace=USEC
26 Send break trace command when latency > USEC. This is a debug‐
27 ging option to control the latency tracer in the realtime pre‐
28 emption patch. It is useful to track down unexpected large la‐
29 tencies of a system.
30 -d, --distance=DIST
32 Set the distance of thread intervals in microseconds (default is
33 500 us). When cyclictest is called with the -t option and more
34 than one thread is created, then this distance value is added to
35 the interval of the threads: Interval(thread N) = Inter‐
36 val(thread N-1) + DIST
37 -D, --duration=TIME
39 Specify a length for the test run.
40 Append 'm', 'h', or 'd' to specify minutes, hours or days.
41 -h, --help
43 Print help message.
44 -i, --interval=INTV
46 Set the base interval of the thread(s) in microseconds (default
47 is 1000 us). This sets the interval of the first thread. See
48 also -d.
49 --json=FILENAME
51 Write final results into FILENAME, JSON formatted.
52 -l, --loops=LOOPS
54 Set the number of loops. The default is 0 (endless). This option
55 is useful for automated tests with a given number of test cy‐
56 cles. ptsematest is stopped once the number of timer intervals
57 has been reached.
58 -p, --prio=PRIO
60 Set the priority of the process.
61 -q, --quiet
63 Print a summary only on exit. Useful for automated tests, where
64 only the summary output needs to be captured.
65 -S, --smp
67 SMP testing: options -a -t and same priority
68 -t, --threads[=NUM]
70 Set the number of test threads (default is 1, if this option is
71 not given). If NUM is specified, create NUM test threads. If NUM
72 is not specified, NUM is set to the number of available CPUs.
73
75 The following example was running on a 4-way processor:
76 # ptsematest -a -t -p99 -i100 -d25 -l1000000
78 #0: ID8672, P99, CPU0, I100; #1: ID8673, P99, CPU0, Cycles 1000000
79 #2: ID8674, P98, CPU1, I125; #3: ID8675, P98, CPU1, Cycles 811035
80 #4: ID8676, P97, CPU2, I150; #5: ID8677, P97, CPU2, Cycles 668130
81 #6: ID8678, P96, CPU3, I175; #7: ID8679, P96, CPU3, Cycles 589423
82 #1 -> #0, Min 1, Cur 1, Avg 2, Max 11
83 #3 -> #2, Min 1, Cur 2, Avg 2, Max 13
84 #5 -> #4, Min 1, Cur 4, Avg 3, Max 12
85 #7 -> #6, Min 1, Cur 4, Avg 2, Max 12
86
88 Carsten Emde <C.Emde@osadl.org>
89
91 pthread_mutex_lock(3p), pthread_mutex_unlock(3p)
92 0.1 ptsematest(8)