1perf-probe(1)
2=============
3
4NAME
5----
6perf-probe - Define new dynamic tracepoints
7
8SYNOPSIS
9--------
10[verse]
11'perf probe' [options] --add='PROBE' [...]
12or
13'perf probe' [options] PROBE
14or
15'perf probe' [options] --del='[GROUP:]EVENT' [...]
16or
17'perf probe' --list[=[GROUP:]EVENT]
18or
19'perf probe' [options] --line='LINE'
20or
21'perf probe' [options] --vars='PROBEPOINT'
22or
23'perf probe' [options] --funcs
24
25DESCRIPTION
26-----------
27This command defines dynamic tracepoint events, by symbol and registers
28without debuginfo, or by C expressions (C line numbers, C function names,
29and C local variables) with debuginfo.
30
31
32OPTIONS
33-------
34-k::
35--vmlinux=PATH::
36	Specify vmlinux path which has debuginfo (Dwarf binary).
37
38-m::
39--module=MODNAME|PATH::
40	Specify module name in which perf-probe searches probe points
41	or lines. If a path of module file is passed, perf-probe
42	treat it as an offline module (this means you can add a probe on
43        a module which has not been loaded yet).
44
45-s::
46--source=PATH::
47	Specify path to kernel source.
48
49-v::
50--verbose::
51        Be more verbose (show parsed arguments, etc).
52	Can not use with -q.
53
54-q::
55--quiet::
56	Be quiet (do not show any messages including errors).
57	Can not use with -v.
58
59-a::
60--add=::
61	Define a probe event (see PROBE SYNTAX for detail).
62
63-d::
64--del=::
65	Delete probe events. This accepts glob wildcards('*', '?') and character
66	classes(e.g. [a-z], [!A-Z]).
67
68-l::
69--list[=[GROUP:]EVENT]::
70	List up current probe events. This can also accept filtering patterns of event names.
71
72-L::
73--line=::
74	Show source code lines which can be probed. This needs an argument
75	which specifies a range of the source code. (see LINE SYNTAX for detail)
76
77-V::
78--vars=::
79	Show available local variables at given probe point. The argument
80	syntax is same as PROBE SYNTAX, but NO ARGs.
81
82--externs::
83	(Only for --vars) Show external defined variables in addition to local
84	variables.
85
86--no-inlines::
87	(Only for --add) Search only for non-inlined functions. The functions
88	which do not have instances are ignored.
89
90-F::
91--funcs[=FILTER]::
92	Show available functions in given module or kernel. With -x/--exec,
93	can also list functions in a user space executable / shared library.
94	This also can accept a FILTER rule argument.
95
96--filter=FILTER::
97	(Only for --vars and --funcs) Set filter. FILTER is a combination of glob
98	pattern, see FILTER PATTERN for detail.
99	Default FILTER is "!__k???tab_* & !__crc_*" for --vars, and "!_*"
100	for --funcs.
101	If several filters are specified, only the last filter is used.
102
103-f::
104--force::
105	Forcibly add events with existing name.
106
107-n::
108--dry-run::
109	Dry run. With this option, --add and --del doesn't execute actual
110	adding and removal operations.
111
112--max-probes=NUM::
113	Set the maximum number of probe points for an event. Default is 128.
114
115-x::
116--exec=PATH::
117	Specify path to the executable or shared library file for user
118	space tracing. Can also be used with --funcs option.
119
120--demangle::
121	Demangle application symbols. --no-demangle is also available
122	for disabling demangling.
123
124--demangle-kernel::
125	Demangle kernel symbols. --no-demangle-kernel is also available
126	for disabling kernel demangling.
127
128In absence of -m/-x options, perf probe checks if the first argument after
129the options is an absolute path name. If its an absolute path, perf probe
130uses it as a target module/target user space binary to probe.
131
132PROBE SYNTAX
133------------
134Probe points are defined by following syntax.
135
136    1) Define event based on function name
137     [EVENT=]FUNC[@SRC][:RLN|+OFFS|%return|;PTN] [ARG ...]
138
139    2) Define event based on source file with line number
140     [EVENT=]SRC:ALN [ARG ...]
141
142    3) Define event based on source file with lazy pattern
143     [EVENT=]SRC;PTN [ARG ...]
144
145
146'EVENT' specifies the name of new event, if omitted, it will be set the name of the probed function. Currently, event group name is set as 'probe'.
147'FUNC' specifies a probed function name, and it may have one of the following options; '+OFFS' is the offset from function entry address in bytes, ':RLN' is the relative-line number from function entry line, and '%return' means that it probes function return. And ';PTN' means lazy matching pattern (see LAZY MATCHING). Note that ';PTN' must be the end of the probe point definition.  In addition, '@SRC' specifies a source file which has that function.
148It is also possible to specify a probe point by the source line number or lazy matching by using 'SRC:ALN' or 'SRC;PTN' syntax, where 'SRC' is the source file path, ':ALN' is the line number and ';PTN' is the lazy matching pattern.
149'ARG' specifies the arguments of this probe point, (see PROBE ARGUMENT).
150
151PROBE ARGUMENT
152--------------
153Each probe argument follows below syntax.
154
155 [NAME=]LOCALVAR|$retval|%REG|@SYMBOL[:TYPE]
156
157'NAME' specifies the name of this argument (optional). You can use the name of local variable, local data structure member (e.g. var->field, var.field2), local array with fixed index (e.g. array[1], var->array[0], var->pointer[2]), or kprobe-tracer argument format (e.g. $retval, %ax, etc). Note that the name of this argument will be set as the last member name if you specify a local data structure member (e.g. field2 for 'var->field1.field2'.)
158'$vars' and '$params' special arguments are also available for NAME, '$vars' is expanded to the local variables (including function parameters) which can access at given probe point. '$params' is expanded to only the function parameters.
159'TYPE' casts the type of this argument (optional). If omitted, perf probe automatically set the type based on debuginfo. You can specify 'string' type only for the local variable or structure member which is an array of or a pointer to 'char' or 'unsigned char' type.
160
161On x86 systems %REG is always the short form of the register: for example %AX. %RAX or %EAX is not valid.
162
163LINE SYNTAX
164-----------
165Line range is described by following syntax.
166
167 "FUNC[@SRC][:RLN[+NUM|-RLN2]]|SRC[:ALN[+NUM|-ALN2]]"
168
169FUNC specifies the function name of showing lines. 'RLN' is the start line
170number from function entry line, and 'RLN2' is the end line number. As same as
171probe syntax, 'SRC' means the source file path, 'ALN' is start line number,
172and 'ALN2' is end line number in the file. It is also possible to specify how
173many lines to show by using 'NUM'. Moreover, 'FUNC@SRC' combination is good
174for searching a specific function when several functions share same name.
175So, "source.c:100-120" shows lines between 100th to l20th in source.c file. And "func:10+20" shows 20 lines from 10th line of func function.
176
177LAZY MATCHING
178-------------
179 The lazy line matching is similar to glob matching but ignoring spaces in both of pattern and target. So this accepts wildcards('*', '?') and character classes(e.g. [a-z], [!A-Z]).
180
181e.g.
182 'a=*' can matches 'a=b', 'a = b', 'a == b' and so on.
183
184This provides some sort of flexibility and robustness to probe point definitions against minor code changes. For example, actual 10th line of schedule() can be moved easily by modifying schedule(), but the same line matching 'rq=cpu_rq*' may still exist in the function.)
185
186FILTER PATTERN
187--------------
188 The filter pattern is a glob matching pattern(s) to filter variables.
189 In addition, you can use "!" for specifying filter-out rule. You also can give several rules combined with "&" or "|", and fold those rules as one rule by using "(" ")".
190
191e.g.
192 With --filter "foo* | bar*", perf probe -V shows variables which start with "foo" or "bar".
193 With --filter "!foo* & *bar", perf probe -V shows variables which don't start with "foo" and end with "bar", like "fizzbar". But "foobar" is filtered out.
194
195EXAMPLES
196--------
197Display which lines in schedule() can be probed:
198
199 ./perf probe --line schedule
200
201Add a probe on schedule() function 12th line with recording cpu local variable:
202
203 ./perf probe schedule:12 cpu
204 or
205 ./perf probe --add='schedule:12 cpu'
206
207 this will add one or more probes which has the name start with "schedule".
208
209 Add probes on lines in schedule() function which calls update_rq_clock().
210
211 ./perf probe 'schedule;update_rq_clock*'
212 or
213 ./perf probe --add='schedule;update_rq_clock*'
214
215Delete all probes on schedule().
216
217 ./perf probe --del='schedule*'
218
219Add probes at zfree() function on /bin/zsh
220
221 ./perf probe -x /bin/zsh zfree or ./perf probe /bin/zsh zfree
222
223Add probes at malloc() function on libc
224
225 ./perf probe -x /lib/libc.so.6 malloc or ./perf probe /lib/libc.so.6 malloc
226
227SEE ALSO
228--------
229linkperf:perf-trace[1], linkperf:perf-record[1]
230