Specify vmlinux path which has debuginfo (Dwarf binary). Only
when using this with --definition, you can give an offline
Specify module name in which perf-probe searches probe points or
lines. If a path of module file is passed, perf-probe treat it as
an offline module (this means you can add a probe on a module
which has not been loaded yet).
Specify path to kernel source.
Be more verbose (show parsed arguments, etc). Can not use with
Be quiet (do not show any messages including errors). Can not use
Define a probe event (see PROBE SYNTAX for detail).
Delete probe events. This accepts glob wildcards(*, ?) and
character classes(e.g. [a-z], [!A-Z]).
List up current probe events. This can also accept filtering
patterns of event names. When this is used with --cache, perf
shows all cached probes instead of the live probes.
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)
Show available local variables at given probe point. The argument
syntax is same as PROBE SYNTAX, but NO ARGs.
(Only for --vars) Show external defined variables in addition to
(Only for --add) Search only for non-inlined functions. The
functions which do not have instances are ignored.
Show available functions in given module or kernel. With
-x/--exec, can also list functions in a user space executable /
shared library. This also can accept a FILTER rule argument.
Show trace-event definition converted from given probe-event
instead of write it into tracing/[k,u]probe_events.
(Only for --vars and --funcs) Set filter. FILTER is a combination
of glob pattern, see FILTER PATTERN for detail. Default FILTER is
"!k???tab_* & !crc_*" for --vars, and "!_*" for --funcs. If
several filters are specified, only the last filter is used.
Forcibly add events with existing name.
Dry run. With this option, --add and --del doesn’t execute actual
adding and removal operations.
(With --add) Cache the probes. Any events which successfully
added are also stored in the cache file. (With --list) Show
cached probes. (With --del) Remove cached probes.
Set the maximum number of probe points for an event. Default is
Specify path to the executable or shared library file for user
space tracing. Can also be used with --funcs option.
Demangle application symbols. --no-demangle is also available for
Demangle kernel symbols. --no-demangle-kernel is also available
for disabling kernel demangling.
In absence of -m/-x options, perf probe checks if the first argument
after the options is an absolute path name. If its an absolute path,
perf probe uses it as a target module/target user space binary to
Probe points are defined by following syntax.
1) Define event based on function name
[[GROUP:]EVENT=]FUNC[@SRC][:RLN|+OFFS|%return|;PTN] [ARG ...]
2) Define event based on source file with line number
[[GROUP:]EVENT=]SRC:ALN [ARG ...]
3) Define event based on source file with lazy pattern
[[GROUP:]EVENT=]SRC;PTN [ARG ...]
4) Pre-defined SDT events or cached event with name
EVENT specifies the name of new event, if omitted, it will be set the
name of the probed function. You can also specify a group name by
GROUP, if omitted, set probe is used for kprobe and probe_<bin> is
used for uprobe. Note that using existing group name can conflict
with other events. Especially, using the group name reserved for
kernel modules can hide embedded events in the modules. 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. It 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. ARG specifies the
arguments of this probe point, (see PROBE ARGUMENT). SDTEVENT and
PROVIDER is the pre-defined event name which is defined by user SDT
(Statically Defined Tracing) or the pre-cached probes with event
name. Note that before using the SDT event, the target binary (on
which SDT events are defined) must be scanned by
perf-buildid-cache(1) to make SDT events as cached events.
For details of the SDT, see below.
Each probe argument follows below syntax.
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,
var→array, var→pointer), 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.) $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.
TYPE casts the type of this argument (optional). If omitted, perf
probe automatically set the type based on debuginfo (*). Currently,
basic types (u8/u16/u32/u64/s8/s16/s32/s64), hexadecimal integers
(x/x8/x16/x32/x64), signedness casting (u/s), "string" and bitfield
are supported. (see TYPES for detail) On x86 systems %REG is always
the short form of the register: for example %AX. %RAX or %EAX is not
Basic types (u8/u16/u32/u64/s8/s16/s32/s64) and hexadecimal integers
(x8/x16/x32/x64) are integer types. Prefix s and u means those types
are signed and unsigned respectively, and x means that is shown in
hexadecimal format. Traced arguments are shown in decimal (sNN/uNN)
or hex (xNN). You can also use s or u to specify only signedness and
leave its size auto-detected by perf probe. Moreover, you can use x
to explicitly specify to be shown in hexadecimal (the size is also
auto-detected). String type is a special type, which fetches a
"null-terminated" string from kernel space. This means it will fail
and store NULL if the string container has been paged out. 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.
Bitfield is another special type, which takes 3 parameters,
bit-width, bit-offset, and container-size (usually 32). The syntax
Line range is described by following syntax.
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.
Moreover, FUNC@SRC combination is good for searching a specific
function when several functions share same name. 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
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]).
e.g. a=* can matches a=b, a = b, a == b and so on.
This 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.)
The filter pattern is a glob matching pattern(s) to filter variables.
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 "(" ")".
e.g. With --filter "foo* | bar*", perf probe -V shows variables which
start with "foo" or "bar". 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.
Display which lines in schedule() can be probed:
./perf probe --line schedule
Add a probe on schedule() function 12th line with recording cpu local
./perf probe schedule:12 cpu
./perf probe --add='schedule:12 cpu'
this will add one or more probes which has the name start with "schedule".
Add probes on lines in schedule() function which calls update_rq_clock().
./perf probe 'schedule;update_rq_clock*'
./perf probe --add='schedule;update_rq_clock*'
Delete all probes on schedule().
./perf probe --del='schedule*'
Add probes at zfree() function on /bin/zsh
./perf probe -x /bin/zsh zfree or ./perf probe /bin/zsh zfree
Add probes at malloc() function on libc
./perf probe -x /lib/libc.so.6 malloc or ./perf probe /lib/libc.so.6 malloc
This page is part of the perf (Performance analysis tools for Linux
(in Linux source tree)) project. Information about the project can
be found at ⟨https://perf.wiki.kernel.org/index.php/Main_Page⟩. If
you have a bug report for this manual page, send it to
email@example.com. This page was obtained from the
project's upstream Git repository
2017-03-13. If you discover any rendering problems in this HTML ver‐
sion of the page, or you believe there is a better or more up-to-date
source for the page, or you have corrections or improvements to the
information in this COLOPHON (which is not part of the original man‐
ual page), send a mail to firstname.lastname@example.org
perf 02/18/2017 PERF-PROBE(1)