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-rw-r--r--tools/perf/Documentation/perf-probe.txt30
1 files changed, 27 insertions, 3 deletions
diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt
index 5fe63c0ca80c..34202b1be0bb 100644
--- a/tools/perf/Documentation/perf-probe.txt
+++ b/tools/perf/Documentation/perf-probe.txt
@@ -61,11 +61,19 @@ PROBE SYNTAX
61------------ 61------------
62Probe points are defined by following syntax. 62Probe points are defined by following syntax.
63 63
64 "[EVENT=]FUNC[+OFFS|:RLN|%return][@SRC]|SRC:ALN [ARG ...]" 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
65 73
66'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'. 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'.
67'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. In addition, 'SRC' specifies a source file which has that function. 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.
68It is also possible to specify a probe point by the source line number by using 'SRC:ALN' syntax, where 'SRC' is the source file path and 'ALN' is the line number. 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.
69'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). 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).
70 78
71LINE SYNTAX 79LINE SYNTAX
@@ -81,6 +89,16 @@ and 'ALN2' is end line number in the file. It is also possible to specify how
81many lines to show by using 'NUM'. 89many lines to show by using 'NUM'.
82So, "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. 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.
83 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
84EXAMPLES 102EXAMPLES
85-------- 103--------
86Display which lines in schedule() can be probed: 104Display which lines in schedule() can be probed:
@@ -95,6 +113,12 @@ Add a probe on schedule() function 12th line with recording cpu local variable:
95 113
96 this will add one or more probes which has the name start with "schedule". 114 this will add one or more probes which has the name start with "schedule".
97 115
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
98Delete all probes on schedule(). 122Delete all probes on schedule().
99 123
100 ./perf probe --del='schedule*' 124 ./perf probe --del='schedule*'