diff options
Diffstat (limited to 'tools/perf/Documentation/perf-probe.txt')
| -rw-r--r-- | tools/perf/Documentation/perf-probe.txt | 42 |
1 files changed, 35 insertions, 7 deletions
diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt index 3a8a9ba2b..b303bcdd8 100644 --- a/tools/perf/Documentation/perf-probe.txt +++ b/tools/perf/Documentation/perf-probe.txt @@ -67,7 +67,10 @@ OPTIONS -l:: --list[=[GROUP:]EVENT]:: - List up current probe events. This can also accept filtering patterns of event names. + 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. -L:: --line=:: @@ -109,6 +112,12 @@ OPTIONS Dry run. With this option, --add and --del doesn't execute actual adding and removal operations. +--cache:: + (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. + --max-probes=NUM:: Set the maximum number of probe points for an event. Default is 128. @@ -134,19 +143,30 @@ PROBE SYNTAX Probe points are defined by following syntax. 1) Define event based on function name - [EVENT=]FUNC[@SRC][:RLN|+OFFS|%return|;PTN] [ARG ...] + [[GROUP:]EVENT=]FUNC[@SRC][:RLN|+OFFS|%return|;PTN] [ARG ...] 2) Define event based on source file with line number - [EVENT=]SRC:ALN [ARG ...] + [[GROUP:]EVENT=]SRC:ALN [ARG ...] 3) Define event based on source file with lazy pattern - [EVENT=]SRC;PTN [ARG ...] + [[GROUP:]EVENT=]SRC;PTN [ARG ...] + 4) Pre-defined SDT events or cached event with name + %[sdt_PROVIDER:]SDTEVENT + or, + sdt_PROVIDER:SDTEVENT -'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'. +'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 linkperf:perf-buildid-cache[1] to make SDT events as cached events. + +For details of the SDT, see below. +https://sourceware.org/gdb/onlinedocs/gdb/Static-Probe-Points.html PROBE ARGUMENT -------------- @@ -156,10 +176,18 @@ 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[1], var->array[0], var->pointer[2]), 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. 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. +'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), 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 valid. +TYPES +----- +Basic types (u8/u16/u32/u64/s8/s16/s32/s64) are integer types. Prefix 's' and 'u' means those types are signed and unsigned respectively. Traced arguments are shown in decimal (signed) or hex (unsigned). You can also use 's' or 'u' to specify only signedness and leave its size auto-detected by perf probe. +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 is; + + b<bit-width>@<bit-offset>/<container-size> + LINE SYNTAX ----------- Line range is described by following syntax. @@ -226,4 +254,4 @@ Add probes at malloc() function on libc SEE ALSO -------- -linkperf:perf-trace[1], linkperf:perf-record[1] +linkperf:perf-trace[1], linkperf:perf-record[1], linkperf:perf-buildid-cache[1] |