linux-kernel - [PATCH 01/31] perf tools: Always use non inlined file name for 'srcfile' sort key

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Date:	Fri,  4 Sep 2015 13:44:45 -0300
From:	Arnaldo Carvalho de Melo <acme@...nel.org>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	linux-kernel@...r.kernel.org, Andi Kleen <ak@...ux.intel.com>,
	Jiri Olsa <jolsa@...nel.org>,
	Arnaldo Carvalho de Melo <acme@...hat.com>
Subject: [PATCH 01/31] perf tools: Always use non inlined file name for 'srcfile' sort key

From: Andi Kleen <ak@...ux.intel.com>

When profiling the kernel with the 'srcfile' sort key it's common to
"get stuck" in include. For example a lot of code uses current or other
inlines, so they get accounted to some random include file. This is not
very useful as a high level categorization.

For example just profiling the idle loop usually shows mostly inlines,
so you never see the actual cpuidle file.

This patch changes the 'srcfile' sort key to always unwind the inline
stack using BFD/DWARF. So we always account to the base function that
called the inline.

In a few cases include is still shown (for example for MSR accesses),
but that is because they get inlining expanded as part of assigning to a
global function pointer. For the majority it works fine though.

v2: Use simpler while loop. Add maximum iteration count.

Signed-off-by: Andi Kleen <ak@...ux.intel.com>
Cc: Jiri Olsa <jolsa@...nel.org>
Link: http://lkml.kernel.org/r/1441133239-31254-1-git-send-email-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@...hat.com>
---
 tools/perf/util/sort.c    |  4 ++--
 tools/perf/util/srcline.c | 29 ++++++++++++++++++++++++-----
 tools/perf/util/util.h    |  2 ++
 3 files changed, 28 insertions(+), 7 deletions(-)

diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c
index 7e3871606df3..a97bceeac0e7 100644
--- a/tools/perf/util/sort.c
+++ b/tools/perf/util/sort.c
@@ -328,8 +328,8 @@ static char *get_srcfile(struct hist_entry *e)
 	char *sf, *p;
 	struct map *map = e->ms.map;
 
-	sf = get_srcline(map->dso, map__rip_2objdump(map, e->ip),
-			 e->ms.sym, true);
+	sf = __get_srcline(map->dso, map__rip_2objdump(map, e->ip),
+			 e->ms.sym, false, true);
 	if (!strcmp(sf, SRCLINE_UNKNOWN))
 		return no_srcfile;
 	p = strchr(sf, ':');
diff --git a/tools/perf/util/srcline.c b/tools/perf/util/srcline.c
index fc08248f08ca..b4db3f48e3b0 100644
--- a/tools/perf/util/srcline.c
+++ b/tools/perf/util/srcline.c
@@ -149,8 +149,11 @@ static void addr2line_cleanup(struct a2l_data *a2l)
 	free(a2l);
 }
 
+#define MAX_INLINE_NEST 1024
+
 static int addr2line(const char *dso_name, u64 addr,
-		     char **file, unsigned int *line, struct dso *dso)
+		     char **file, unsigned int *line, struct dso *dso,
+		     bool unwind_inlines)
 {
 	int ret = 0;
 	struct a2l_data *a2l = dso->a2l;
@@ -170,6 +173,15 @@ static int addr2line(const char *dso_name, u64 addr,
 
 	bfd_map_over_sections(a2l->abfd, find_address_in_section, a2l);
 
+	if (a2l->found && unwind_inlines) {
+		int cnt = 0;
+
+		while (bfd_find_inliner_info(a2l->abfd, &a2l->filename,
+					     &a2l->funcname, &a2l->line) &&
+		       cnt++ < MAX_INLINE_NEST)
+			;
+	}
+
 	if (a2l->found && a2l->filename) {
 		*file = strdup(a2l->filename);
 		*line = a2l->line;
@@ -197,7 +209,8 @@ void dso__free_a2l(struct dso *dso)
 
 static int addr2line(const char *dso_name, u64 addr,
 		     char **file, unsigned int *line_nr,
-		     struct dso *dso __maybe_unused)
+		     struct dso *dso __maybe_unused,
+		     bool unwind_inlines __maybe_unused)
 {
 	FILE *fp;
 	char cmd[PATH_MAX];
@@ -254,8 +267,8 @@ void dso__free_a2l(struct dso *dso __maybe_unused)
  */
 #define A2L_FAIL_LIMIT 123
 
-char *get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
-		  bool show_sym)
+char *__get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
+		  bool show_sym, bool unwind_inlines)
 {
 	char *file = NULL;
 	unsigned line = 0;
@@ -276,7 +289,7 @@ char *get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
 	if (!strncmp(dso_name, "/tmp/perf-", 10))
 		goto out;
 
-	if (!addr2line(dso_name, addr, &file, &line, dso))
+	if (!addr2line(dso_name, addr, &file, &line, dso, unwind_inlines))
 		goto out;
 
 	if (asprintf(&srcline, "%s:%u",
@@ -310,3 +323,9 @@ void free_srcline(char *srcline)
 	if (srcline && strcmp(srcline, SRCLINE_UNKNOWN) != 0)
 		free(srcline);
 }
+
+char *get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
+		  bool show_sym)
+{
+	return __get_srcline(dso, addr, sym, show_sym, false);
+}
diff --git a/tools/perf/util/util.h b/tools/perf/util/util.h
index 291be1d84bc3..09c1a8b7b4c2 100644
--- a/tools/perf/util/util.h
+++ b/tools/perf/util/util.h
@@ -321,6 +321,8 @@ struct symbol;
 extern bool srcline_full_filename;
 char *get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
 		  bool show_sym);
+char *__get_srcline(struct dso *dso, u64 addr, struct symbol *sym,
+		  bool show_sym, bool unwind_inlines);
 void free_srcline(char *srcline);
 
 int filename__read_str(const char *filename, char **buf, size_t *sizep);
-- 
2.1.0

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