1 perf-probe(1) 2 ============= 3 4 NAME 5 ---- 6 perf-probe - Define new dynamic tracepoints 7 8 SYNOPSIS 9 -------- 10 [verse] 11 'perf probe' [options] --add='PROBE' [...] 12 or 13 'perf probe' [options] PROBE 14 or 15 'perf probe' [options] --del='[GROUP:]EVENT' [...] 16 or 17 'perf probe' --list 18 or 19 'perf probe' [options] --line='LINE' 20 or 21 'perf probe' [options] --vars='PROBEPOINT' 22 23 DESCRIPTION 24 ----------- 25 This command defines dynamic tracepoint events, by symbol and registers 26 without debuginfo, or by C expressions (C line numbers, C function names, 27 and C local variables) with debuginfo. 28 29 30 OPTIONS 31 ------- 32 -k:: 33 --vmlinux=PATH:: 34 Specify vmlinux path which has debuginfo (Dwarf binary). 35 36 -m:: 37 --module=MODNAME:: 38 Specify module name in which perf-probe searches probe points 39 or lines. 40 41 -s:: 42 --source=PATH:: 43 Specify path to kernel source. 44 45 -v:: 46 --verbose:: 47 Be more verbose (show parsed arguments, etc). 48 49 -a:: 50 --add=:: 51 Define a probe event (see PROBE SYNTAX for detail). 52 53 -d:: 54 --del=:: 55 Delete probe events. This accepts glob wildcards('*', '?') and character 56 classes(e.g. [a-z], [!A-Z]). 57 58 -l:: 59 --list:: 60 List up current probe events. 61 62 -L:: 63 --line=:: 64 Show source code lines which can be probed. This needs an argument 65 which specifies a range of the source code. (see LINE SYNTAX for detail) 66 67 -V:: 68 --vars=:: 69 Show available local variables at given probe point. The argument 70 syntax is same as PROBE SYNTAX, but NO ARGs. 71 72 --externs:: 73 (Only for --vars) Show external defined variables in addition to local 74 variables. 75 76 -F:: 77 --funcs:: 78 Show available functions in given module or kernel. 79 80 --filter=FILTER:: 81 (Only for --vars and --funcs) Set filter. FILTER is a combination of glob 82 pattern, see FILTER PATTERN for detail. 83 Default FILTER is "!__k???tab_* & !__crc_*" for --vars, and "!_*" 84 for --funcs. 85 If several filters are specified, only the last filter is used. 86 87 -f:: 88 --force:: 89 Forcibly add events with existing name. 90 91 -n:: 92 --dry-run:: 93 Dry run. With this option, --add and --del doesn't execute actual 94 adding and removal operations. 95 96 --max-probes:: 97 Set the maximum number of probe points for an event. Default is 128. 98 99 PROBE SYNTAX 100 ------------ 101 Probe points are defined by following syntax. 102 103 1) Define event based on function name 104 [EVENT=]FUNC[@SRC][:RLN|+OFFS|%return|;PTN] [ARG ...] 105 106 2) Define event based on source file with line number 107 [EVENT=]SRC:ALN [ARG ...] 108 109 3) Define event based on source file with lazy pattern 110 [EVENT=]SRC;PTN [ARG ...] 111 112 113 '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'. 114 '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. 115 It 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. 116 'ARG' specifies the arguments of this probe point, (see PROBE ARGUMENT). 117 118 PROBE ARGUMENT 119 -------------- 120 Each probe argument follows below syntax. 121 122 [NAME=]LOCALVAR|$retval|%REG|@SYMBOL[:TYPE] 123 124 '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'.) 125 '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. 126 127 LINE SYNTAX 128 ----------- 129 Line range is described by following syntax. 130 131 "FUNC[@SRC][:RLN[+NUM|-RLN2]]|SRC[:ALN[+NUM|-ALN2]]" 132 133 FUNC specifies the function name of showing lines. 'RLN' is the start line 134 number from function entry line, and 'RLN2' is the end line number. As same as 135 probe syntax, 'SRC' means the source file path, 'ALN' is start line number, 136 and 'ALN2' is end line number in the file. It is also possible to specify how 137 many lines to show by using 'NUM'. Moreover, 'FUNC@SRC' combination is good 138 for searching a specific function when several functions share same name. 139 So, "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. 140 141 LAZY MATCHING 142 ------------- 143 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]). 144 145 e.g. 146 'a=*' can matches 'a=b', 'a = b', 'a == b' and so on. 147 148 This 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.) 149 150 FILTER PATTERN 151 -------------- 152 The filter pattern is a glob matching pattern(s) to filter variables. 153 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 "(" ")". 154 155 e.g. 156 With --filter "foo* | bar*", perf probe -V shows variables which start with "foo" or "bar". 157 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. 158 159 EXAMPLES 160 -------- 161 Display which lines in schedule() can be probed: 162 163 ./perf probe --line schedule 164 165 Add a probe on schedule() function 12th line with recording cpu local variable: 166 167 ./perf probe schedule:12 cpu 168 or 169 ./perf probe --add='schedule:12 cpu' 170 171 this will add one or more probes which has the name start with "schedule". 172 173 Add probes on lines in schedule() function which calls update_rq_clock(). 174 175 ./perf probe 'schedule;update_rq_clock*' 176 or 177 ./perf probe --add='schedule;update_rq_clock*' 178 179 Delete all probes on schedule(). 180 181 ./perf probe --del='schedule*' 182 183 184 SEE ALSO 185 -------- 186 linkperf:perf-trace[1], linkperf:perf-record[1] 187
