linux-kernel - [PATCH perf/core v4 12/19] perf probe: Add group name support

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Message-Id: <20160426090404.11891.64668.stgit@devbox>
Date:	Tue, 26 Apr 2016 18:04:04 +0900
From:	Masami Hiramatsu <mhiramat@...nel.org>
To:	Arnaldo Carvalho de Melo <acme@...nel.org>
Cc:	Masami Hiramatsu <mhiramat@...nel.org>,
	linux-kernel@...r.kernel.org, Namhyung Kim <namhyung@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...hat.com>,
	Hemant Kumar <hemant@...ux.vnet.ibm.com>,
	Ananth N Mavinakayanahalli <ananth@...ux.vnet.ibm.com>
Subject: [PATCH perf/core v4 12/19] perf probe: Add group name support

From: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>

Allow user to set group name for adding new event.
Note that user must ensure that the group name doesn't
conflict with existing group name carefully.
E.g. Existing group name can conflict with other events.
Especially, using the group name reserved for kernel
modules can hide kernel embedded events when loading
modules.

Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@...achi.com>
Signed-off-by: Masami Hiramatsu <mhiramat@...nel.org>
---
 Changes in v4:
  - Update Documentation/perf-probe.txt too.
---
 tools/perf/Documentation/perf-probe.txt |   10 ++++++----
 tools/perf/util/probe-event.c           |   23 ++++++++++++++---------
 2 files changed, 20 insertions(+), 13 deletions(-)

diff --git a/tools/perf/Documentation/perf-probe.txt b/tools/perf/Documentation/perf-probe.txt
index 8d09173..7a258e9 100644
--- a/tools/perf/Documentation/perf-probe.txt
+++ b/tools/perf/Documentation/perf-probe.txt
@@ -143,16 +143,18 @@ 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 ...]
 
 
-'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, '@...' 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).
diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
index de5460d..d4286bb 100644
--- a/tools/perf/util/probe-event.c
+++ b/tools/perf/util/probe-event.c
@@ -1153,10 +1153,8 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
 	bool file_spec = false;
 	/*
 	 * <Syntax>
-	 * perf probe [EVENT=]SRC[:LN|;PTN]
-	 * perf probe [EVENT=]FUNC[@SRC][+OFFS|%return|:LN|;PAT]
-	 *
-	 * TODO:Group name support
+	 * perf probe [GRP:][EVENT=]SRC[:LN|;PTN]
+	 * perf probe [GRP:][EVENT=]FUNC[@SRC][+OFFS|%return|:LN|;PAT]
 	 */
 	if (!arg)
 		return -EINVAL;
@@ -1165,11 +1163,19 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
 	if (ptr && *ptr == '=') {	/* Event name */
 		*ptr = '\0';
 		tmp = ptr + 1;
-		if (strchr(arg, ':')) {
-			semantic_error("Group name is not supported yet.\n");
-			return -ENOTSUP;
-		}
+		ptr = strchr(arg, ':');
+		if (ptr) {
+			*ptr = '\0';
+			if (!is_c_func_name(arg))
+				goto not_fname;
+			pev->group = strdup(arg);
+			if (!pev->group)
+				return -ENOMEM;
+			arg = ptr + 1;
+		} else
+			pev->group = NULL;
 		if (!is_c_func_name(arg)) {
+not_fname:
 			semantic_error("%s is bad for event name -it must "
 				       "follow C symbol-naming rule.\n", arg);
 			return -EINVAL;
@@ -1177,7 +1183,6 @@ static int parse_perf_probe_point(char *arg, struct perf_probe_event *pev)
 		pev->event = strdup(arg);
 		if (pev->event == NULL)
 			return -ENOMEM;
-		pev->group = NULL;
 		arg = tmp;
 	}