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 60PROBE SYNTAX 61------------ 62Probe points are defined by following syntax. 63 64 1) Define event based on function name 65 [EVENT=]FUNC[@SRC][:RLN|+OFFS|%return|;PTN] [ARG ...] 66 67 2) Define event based on source file with line number 68 [EVENT=]SRC:ALN [ARG ...] 69 70 3) Define event based on source file with lazy pattern 71 [EVENT=]SRC;PTN [ARG ...] 72 73 74'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'. 75'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. 76It 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. 77'ARG' specifies the arguments of this probe point. You can use the name of local variable, or kprobe-tracer argument format (e.g. $retval, %ax, etc). 78 79LINE SYNTAX 80----------- 81Line range is descripted by following syntax. 82 83 "FUNC[:RLN[+NUM|:RLN2]]|SRC:ALN[+NUM|:ALN2]" 84 85FUNC specifies the function name of showing lines. 'RLN' is the start line 86number from function entry line, and 'RLN2' is the end line number. As same as 87probe syntax, 'SRC' means the source file path, 'ALN' is start line number, 88and 'ALN2' is end line number in the file. It is also possible to specify how 89many lines to show by using 'NUM'. 90So, "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. 91 92LAZY MATCHING 93------------- 94 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]). 95 96e.g. 97 'a=*' can matches 'a=b', 'a = b', 'a == b' and so on. 98 99This 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.) 100 101 102EXAMPLES 103-------- 104Display which lines in schedule() can be probed: 105 106 ./perf probe --line schedule 107 108Add a probe on schedule() function 12th line with recording cpu local variable: 109 110 ./perf probe schedule:12 cpu 111 or 112 ./perf probe --add='schedule:12 cpu' 113 114 this will add one or more probes which has the name start with "schedule". 115 116 Add probes on lines in schedule() function which calls update_rq_clock(). 117 118 ./perf probe 'schedule;update_rq_clock*' 119 or 120 ./perf probe --add='schedule;update_rq_clock*' 121 122Delete all probes on schedule(). 123 124 ./perf probe --del='schedule*' 125 126 127SEE ALSO 128-------- 129linkperf:perf-trace[1], linkperf:perf-record[1] 130