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