1pmqtest(8) pmqtest(8)
2
6 pmqtest - Start pairs of threads and measure the latency of interpro‐
7 cess communication with POSIX messages queues
8
10 pmqtest [-a|-a PROC] [-b USEC] [-d DIST] [-D TIME] [-f TO] [-h] [-i
11 INTV] [--json FILENAME] [-l LOOPS] [-p PRIO] [-q] [-S] [-t|-t NUM]
12
14 The program pmqtest starts pairs of threads that are synchronized via
15 mq_send/mw_receive() and measures the latency between sending and re‐
16 ceiving the message.
17
19 -a, --affinity[=PROC]
20 Run on processor number PROC. If PROC is not specified, run on
21 current processor.
22 -b, --breaktrace=USEC
24 Send break trace command when latency > USEC. This is a debug‐
25 ging option to control the latency tracer in the realtime pre‐
26 emption patch. It is useful to track down unexpected large la‐
27 tencies of a system.
28 -d, --distance=DIST
30 Set the distance of thread intervals in microseconds (default is
31 500 us). When pmqtest is called with the -t option and more than
32 one thread is created, then this distance value is added to the
33 interval of the threads: Interval(thread N) = Interval(thread
34 N-1) + DIST
35 -D, --duration=TIME
37 Specify a length for the test run.
38 Append 'm', 'h', or 'd' to specify minutes, hours or days.
39 -h, --help
41 Print help message
42 -f, --forcetimeout=TO
44 Set an artificial delay of the send function to force timeout of
45 the receiver, requires the -T option
46 -i, --interval=INTV
48 Set the base interval of the thread(s) in microseconds (default
49 is 1000 us). This sets the interval of the first thread. See
50 also -d.
51 --json=FILENAME
53 Write final results into FILENAME, JSON formatted.
54 -l, --loops=LOOPS
56 Set the number of loops. The default is 0 (endless). This option
57 is useful for automated tests with a given number of test cy‐
58 cles. pmqtest is stopped once the number of timer intervals has
59 been reached.
60 -p, --prio=PRIO
62 Set the priority of the process.
63 -q, --quiet
65 Print a summary only on exit. Useful for automated tests, where
66 only the summary output needs to be captured.
67 -S, --smp
69 Test mode for symmetric multi-processing, implies -a and -t and
70 uses the same priority on all threads.
71 -t, --threads[=NUM]
73 Set the number of test threads (default is 1, if this option is
74 not given). If NUM is specified, create NUM test threads. If NUM
75 is not specified, NUM is set to the number of available CPUs.
76 -T, --timeout=TO
78 Use mq_timedreceive() instead of mq_receive() and specify time‐
79 out TO in seconds.
80
82 The following example was running on an 8-way processor:
83 # pmqtest -Sp99 -i100 -d0
85 #0: ID10047, P99, CPU0, I100; #1: ID10048, P99, CPU0, Cycles 153695
86 #2: ID10049, P99, CPU1, I100; #3: ID10050, P99, CPU1, Cycles 154211
87 #4: ID10051, P99, CPU2, I100; #5: ID10052, P99, CPU2, Cycles 156823
88 #6: ID10053, P99, CPU3, I100; #7: ID10054, P99, CPU3, Cycles 158202
89 #8: ID10055, P99, CPU4, I100; #9: ID10056, P99, CPU4, Cycles 153399
90 #10: ID10057, P99, CPU5, I100; #11: ID10058, P99, CPU5, Cycles 153992
91 #12: ID10059, P99, CPU6, I100; #13: ID10060, P99, CPU6, Cycles 156576
92 #14: ID10061, P99, CPU7, I100; #15: ID10062, P99, CPU7, Cycles 157957
93 #1 -> #0, Min 1, Cur 8, Avg 5, Max 18
94 #3 -> #2, Min 1, Cur 4, Avg 5, Max 18
95 #5 -> #4, Min 1, Cur 5, Avg 5, Max 19
96 #7 -> #6, Min 1, Cur 4, Avg 4, Max 17
97 #9 -> #8, Min 1, Cur 9, Avg 5, Max 18
98 #11 -> #10, Min 1, Cur 8, Avg 5, Max 18
99 #13 -> #12, Min 1, Cur 4, Avg 5, Max 29
100 #15 -> #14, Min 1, Cur 8, Avg 4, Max 17
101
103 Carsten Emde <C.Emde@osadl.org>
104
106 mq_send(3p), mq_receive(3p)
107 0.1 pmqtest(8)