Commit 7e9fca51 authored Jul 12, 2016 by Masami Hiramatsu Committed by Arnaldo Carvalho de Melo Jul 13, 2016

perf probe: Support a special SDT probe format



Support a special SDT probe format which can omit the '%' prefix only if
the SDT group name starts with "sdt_". So, for example both of
"%sdt_libc:setjump" and "sdt_libc:setjump" are acceptable for perf probe
--add.

E.g. without this:

  # perf probe -a sdt_libc:setjmp
  Semantic error :There is non-digit char in line number.
  ...

With this:

  # perf probe -a sdt_libc:setjmp
  Added new event:
    sdt_libc:setjmp      (on %setjmp in /usr/lib64/libc-2.20.so)

  You can now use it in all perf tools, such as:

  	perf record -e sdt_libc:setjmp -aR sleep 1

Suggested-by: Brendan Gregg <brendan.d.gregg@gmail.com>
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
Cc: Hemant Kumar <hemant@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/146831794674.17065.13359473252168740430.stgit@devbox


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

parent a598180a

tools/perf/Documentation/perf-probe.txt

+3 −1

Original line number	Diff line number	Diff line
		@@ -152,7 +152,9 @@ Probe points are defined by following syntax.
		[[GROUP:]EVENT=]SRC;PTN [ARG ...]

		4) Pre-defined SDT events or cached event with name
		%[PROVIDER:]SDTEVENT
		%[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. 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

tools/perf/util/probe-event.c

+10 −2

Original line number	Diff line number	Diff line
		@@ -1243,8 +1243,16 @@ static int parse_perf_probe_point(char arg, struct perf_probe_event pev)
		if (!arg)
		return -EINVAL;

		if (arg[0] == '%') {
		/*
		* If the probe point starts with '%',
		* or starts with "sdt_" and has a ':' but no '=',
		* then it should be a SDT/cached probe point.
		*/
		if (arg[0] == '%' \|\|
		(!strncmp(arg, "sdt_", 4) &&
		!!strchr(arg, ':') && !strchr(arg, '='))) {
		pev->sdt = true;
		if (arg[0] == '%')
		arg++;
		}