1perf-ftrace(1)
2==============
3
4NAME
5----
6perf-ftrace - simple wrapper for kernel's ftrace functionality
7
8
9SYNOPSIS
10--------
11[verse]
12'perf ftrace' {trace|latency} <command>
13
14DESCRIPTION
15-----------
16The 'perf ftrace' command provides a collection of subcommands which use
17kernel's ftrace infrastructure.
18
19  'perf ftrace trace' is a simple wrapper of the ftrace.  It only supports
20  single thread tracing currently and just reads trace_pipe in text and then
21  write it to stdout.
22
23  'perf ftrace latency' calculates execution latency of a given function
24  (optionally with BPF) and display it as a histogram.
25
26The following options apply to perf ftrace.
27
28COMMON OPTIONS
29--------------
30
31-p::
32--pid=::
33	Trace on existing process id (comma separated list).
34
35--tid=::
36	Trace on existing thread id (comma separated list).
37
38-a::
39--all-cpus::
40	Force system-wide collection.  Scripts run without a <command>
41	normally use -a by default, while scripts run with a <command>
42	normally don't - this option allows the latter to be run in
43	system-wide mode.
44
45-C::
46--cpu=::
47	Only trace for the list of CPUs provided.  Multiple CPUs can
48	be provided as a comma separated list with no space like: 0,1.
49	Ranges of CPUs are specified with -: 0-2.
50	Default is to trace on all online CPUs.
51
52-v::
53--verbose::
54        Increase the verbosity level.
55
56
57OPTIONS for 'perf ftrace trace'
58-------------------------------
59
60-t::
61--tracer=::
62	Tracer to use when neither -G nor -F option is not
63	specified: function_graph or function.
64
65-F::
66--funcs::
67        List available functions to trace. It accepts a pattern to
68        only list interested functions.
69
70-D::
71--delay::
72	Time (ms) to wait before starting tracing after program start.
73
74-m::
75--buffer-size::
76	Set the size of per-cpu tracing buffer, <size> is expected to
77	be a number with appended unit character - B/K/M/G.
78
79--inherit::
80	Trace children processes spawned by our target.
81
82-T::
83--trace-funcs=::
84	Select function tracer and set function filter on the given
85	function (or a glob pattern). Multiple functions can be given
86	by using this option more than once. The function argument also
87	can be a glob pattern. It will be passed to 'set_ftrace_filter'
88	in tracefs.
89
90-N::
91--notrace-funcs=::
92	Select function tracer and do not trace functions given by the
93	argument.  Like -T option, this can be used more than once to
94	specify multiple functions (or glob patterns).  It will be
95	passed to 'set_ftrace_notrace' in tracefs.
96
97--func-opts::
98	List of options allowed to set:
99
100	  - call-graph - Display kernel stack trace for function tracer.
101	  - irq-info   - Display irq context info for function tracer.
102
103-G::
104--graph-funcs=::
105	Select function_graph tracer and set graph filter on the given
106	function (or a glob pattern). This is useful to trace for
107	functions executed from the given function. This can be used more
108	than once to specify multiple functions. It will be passed to
109	'set_graph_function' in tracefs.
110
111-g::
112--nograph-funcs=::
113	Select function_graph tracer and set graph notrace filter on the
114	given function (or a glob pattern). Like -G option, this is useful
115	for the function_graph tracer only and disables tracing for function
116	executed from the given function. This can be used more than once to
117	specify multiple functions. It will be passed to 'set_graph_notrace'
118	in tracefs.
119
120--graph-opts::
121	List of options allowed to set:
122
123	  - nosleep-time - Measure on-CPU time only for function_graph tracer.
124	  - noirqs       - Ignore functions that happen inside interrupt.
125	  - verbose      - Show process names, PIDs, timestamps, etc.
126	  - thresh=<n>   - Setup trace duration threshold in microseconds.
127	  - depth=<n>    - Set max depth for function graph tracer to follow.
128
129
130OPTIONS for 'perf ftrace latency'
131---------------------------------
132
133-T::
134--trace-funcs=::
135	Set the function name to get the histogram.  Unlike perf ftrace trace,
136	it only allows single function to calculate the histogram.
137
138-b::
139--use-bpf::
140	Use BPF to measure function latency instead of using the ftrace (it
141	uses function_graph tracer internally).
142
143-n::
144--use-nsec::
145	Use nano-second instead of micro-second as a base unit of the histogram.
146
147
148SEE ALSO
149--------
150linkperf:perf-record[1], linkperf:perf-trace[1]
151