linux/tools/perf/Documentation/perf-probe.txt

perf-probe(1)
=============

NAME
----
perf-probe - Define new dynamic tracepoints

SYNOPSIS
--------
[verse]
'perf probe' [options] --add='PROBE' [...]
or
'perf probe' [options] PROBE
or
'perf probe' [options] --del='[GROUP:]EVENT' [...]
or
'perf probe' --list
or
'perf probe' --line='FUNC[:RLN[+NUM|:RLN2]]|SRC:ALN[+NUM|:ALN2]'

DESCRIPTION
-----------
This command defines dynamic tracepoint events, by symbol and registers
without debuginfo, or by C expressions (C line numbers, C function names,
and C local variables) with debuginfo.


OPTIONS
-------
-k::
--vmlinux=PATH::
	Specify vmlinux path which has debuginfo (Dwarf binary).

-v::
--verbose::
        Be more verbose (show parsed arguments, etc).

-a::
--add=::
	Define a probe event (see PROBE SYNTAX for detail).

-d::
--del=::
	Delete probe events. This accepts glob wildcards('*', '?') and character
	classes(e.g. [a-z], [!A-Z]).

-l::
--list::
	List up current probe events.

-L::
--line=::
	Show source code lines which can be probed. This needs an argument
	which specifies a range of the source code. (see LINE SYNTAX for detail)

-f::
--force::
	Forcibly add events with existing name.

PROBE SYNTAX
------------
Probe points are defined by following syntax.

 "[EVENT=]FUNC[+OFFS|:RLN|%return][@SRC]|SRC:ALN [ARG ...]"

'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'.
'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.
It 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.
'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).

LINE SYNTAX
-----------
Line range is descripted by following syntax.

 "FUNC[:RLN[+NUM|:RLN2]]|SRC:ALN[+NUM|:ALN2]"

FUNC specifies the function name of showing lines. 'RLN' is the start line
number from function entry line, and 'RLN2' is the end line number. As same as
probe syntax, 'SRC' means the source file path, 'ALN' is start line number,
and 'ALN2' is end line number in the file. It is also possible to specify how
many lines to show by using 'NUM'.
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.

EXAMPLES
--------
Display which lines in schedule() can be probed:

 ./perf probe --line schedule

Add a probe on schedule() function 12th line with recording cpu local variable:

 ./perf probe schedule:12 cpu
 or
 ./perf probe --add='schedule:12 cpu'

 this will add one or more probes which has the name start with "schedule".

Delete all probes on schedule().

 ./perf probe --del='schedule*'


SEE ALSO
--------
linkperf:perf-trace[1], linkperf:perf-record[1]