1 .. SPDX-License-Identifier: GPL-2.0
2
3 ============
4 rtla-hwnoise
5 ============
6 ------------------------------------------
7 Detect and quantify hardware-related noise
8 ------------------------------------------
9
10 :Manual section: 1
11
12 SYNOPSIS
13 ========
14
15 **rtla hwnoise** [*OPTIONS*]
16
17 DESCRIPTION
18 ===========
19
20 **rtla hwnoise** collects the periodic summary
21 running with *interrupts disabled*. By disabli
22 of threads as a consequence, only non-maskable
23 noise is allowed.
24
25 The tool also allows the configurations of the
26 collection of the tracer output.
27
28 OPTIONS
29 =======
30 .. include:: common_osnoise_options.rst
31
32 .. include:: common_top_options.rst
33
34 .. include:: common_options.rst
35
36 EXAMPLE
37 =======
38 In the example below, the **rtla hwnoise** too
39 on a system with 8 cores/16 threads with hyper
40
41 The tool is set to detect any noise higher tha
42 to run for *ten minutes*, displaying a summary
43 end of the session::
44
45 # rtla hwnoise -c 1-7 -T 1 -d 10m -q
46 Hard
47 duration: 0 00:10:00 | time is in us
48 CPU Period Runtime Noise % CPU
49 1 #599 599000000 138 99.
50 2 #599 599000000 85 99.
51 3 #599 599000000 86 99.
52 4 #599 599000000 81 99.
53 5 #599 599000000 85 99.
54 6 #599 599000000 76 99.
55 7 #599 599000000 77 99.
56
57
58 The first column shows the *CPU*, and the seco
59 *Periods* the tool ran during the session. The
60 the tool effectively runs on the CPU. The *Noi
61 all noise that the tool observed, and the *% C
62 between the *Runtime* and *Noise*.
63
64 The *Max Noise* column is the maximum hardware
65 single period, and the *Max Single* is the max
66
67 The *HW* and *NMI* columns show the total numb
68 occurrence observed by the tool.
69
70 For example, *CPU 3* ran *599* periods of *1 s
71 *86 us* of noise during the entire execution,
72 for the application. In the worst single perio
73 noise to the application, but it was certainly
74 noise, as the *Max Single* noise was of *3 us*
75 rate of *six occurrences*/*ten minutes*. The C
76 frequency: around *seven per second*.
77
78 The tool should report *0* hardware-related no
79 For example, by disabling hyper-threading to r
80 and disabling the TSC watchdog to remove the N
81 this using tracing options of **rtla hwnoise**
82 the ideal situation in the same hardware::
83
84 # rtla hwnoise -c 1-7 -T 1 -d 10m -q
85 Hard
86 duration: 0 00:10:00 | time is in us
87 CPU Period Runtime Noise % CPU
88 1 #599 599000000 0 100.
89 2 #599 599000000 0 100.
90 3 #599 599000000 0 100.
91 4 #599 599000000 0 100.
92 5 #599 599000000 0 100.
93 6 #599 599000000 0 100.
94 7 #599 599000000 0 100.
95
96 SEE ALSO
97 ========
98
99 **rtla-osnoise**\(1)
100
101 Osnoise tracer documentation: <https://www.ker
102
103 AUTHOR
104 ======
105 Written by Daniel Bristot de Oliveira <bristot@
106
107 .. include:: common_appendix.rst
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