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 18or 19'perf probe' --line='FUNC[:RLN[+NUM|:RLN2]]|SRC:ALN[+NUM|:ALN2]' 20 21DESCRIPTION 22----------- 23This command defines dynamic tracepoint events, by symbol and registers 24without debuginfo, or by C expressions (C line numbers, C function names, 25and C local variables) with debuginfo. 26 27 28OPTIONS 29------- 30-k:: 31--vmlinux=PATH:: 32 Specify vmlinux path which has debuginfo (Dwarf binary). 33 34-v:: 35--verbose:: 36 Be more verbose (show parsed arguments, etc). 37 38-a:: 39--add=:: 40 Define a probe event (see PROBE SYNTAX for detail). 41 42-d:: 43--del=:: 44 Delete probe events. This accepts glob wildcards('*', '?') and character 45 classes(e.g. [a-z], [!A-Z]). 46 47-l:: 48--list:: 49 List up current probe events. 50 51-L:: 52--line=:: 53 Show source code lines which can be probed. This needs an argument 54 which specifies a range of the source code. (see LINE SYNTAX for detail) 55 56-f:: 57--force:: 58 Forcibly add events with existing name. 59 60-n:: 61--dry-run:: 62 Dry run. With this option, --add and --del doesn't execute actual 63 adding and removal operations. 64 65--max-probes:: 66 Set the maximum number of probe points for an event. Default is 128. 67 68PROBE SYNTAX 69------------ 70Probe points are defined by following syntax. 71 72 1) Define event based on function name 73 [EVENT=]FUNC[@SRC][:RLN|+OFFS|%return|;PTN] [ARG ...] 74 75 2) Define event based on source file with line number 76 [EVENT=]SRC:ALN [ARG ...] 77 78 3) Define event based on source file with lazy pattern 79 [EVENT=]SRC;PTN [ARG ...] 80 81 82'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'. 83'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. 84It 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. 85'ARG' specifies the arguments of this probe point, (see PROBE ARGUMENT). 86 87PROBE ARGUMENT 88-------------- 89Each probe argument follows below syntax. 90 91 [NAME=]LOCALVAR|$retval|%REG|@SYMBOL[:TYPE] 92 93'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), 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'.) 94'TYPE' casts the type of this argument (optional). If omitted, perf probe automatically set the type based on debuginfo. 95 96LINE SYNTAX 97----------- 98Line range is descripted by following syntax. 99 100 "FUNC[:RLN[+NUM|-RLN2]]|SRC:ALN[+NUM|-ALN2]" 101 102FUNC specifies the function name of showing lines. 'RLN' is the start line 103number from function entry line, and 'RLN2' is the end line number. As same as 104probe syntax, 'SRC' means the source file path, 'ALN' is start line number, 105and 'ALN2' is end line number in the file. It is also possible to specify how 106many lines to show by using 'NUM'. 107So, "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. 108 109LAZY MATCHING 110------------- 111 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]). 112 113e.g. 114 'a=*' can matches 'a=b', 'a = b', 'a == b' and so on. 115 116This 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.) 117 118 119EXAMPLES 120-------- 121Display which lines in schedule() can be probed: 122 123 ./perf probe --line schedule 124 125Add a probe on schedule() function 12th line with recording cpu local variable: 126 127 ./perf probe schedule:12 cpu 128 or 129 ./perf probe --add='schedule:12 cpu' 130 131 this will add one or more probes which has the name start with "schedule". 132 133 Add probes on lines in schedule() function which calls update_rq_clock(). 134 135 ./perf probe 'schedule;update_rq_clock*' 136 or 137 ./perf probe --add='schedule;update_rq_clock*' 138 139Delete all probes on schedule(). 140 141 ./perf probe --del='schedule*' 142 143 144SEE ALSO 145-------- 146linkperf:perf-trace[1], linkperf:perf-record[1] 147