[tip:perf/core] perf symbols: Add front end cache for DSO symbol lookup

[tip-bot for Arnaldo Carvalho de Melo <tipbot@zytor.com>]

Commit-ID:  b685ac22b436455db9c9c16b384d7aa4531cdd80
Gitweb:     http://git.kernel.org/tip/b685ac22b436455db9c9c16b384d7aa4531cdd80
Author:     Arnaldo Carvalho de Melo <acme@redhat.com>
AuthorDate: Wed, 22 Jul 2015 12:52:17 -0300
Committer:  Arnaldo Carvalho de Melo <acme@redhat.com>
CommitDate: Thu, 23 Jul 2015 11:28:35 -0300

perf symbols: Add front end cache for DSO symbol lookup

Acked-by: David Ahern <dsahern@gmail.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Borislav Petkov <bp@suse.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/n/tip-voo94tow8wpkcc76mlkny6sc@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/util/dso.h    | 4 ++++
 tools/perf/util/symbol.c | 7 ++++++-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/dso.h b/tools/perf/util/dso.h
index 2fe98bb..c73276d 100644
--- a/tools/perf/util/dso.h
+++ b/tools/perf/util/dso.h
@@ -137,6 +137,10 @@ struct dso {
 	struct rb_node	 rb_node;	/* rbtree node sorted by long name */
 	struct rb_root	 symbols[MAP__NR_TYPES];
 	struct rb_root	 symbol_names[MAP__NR_TYPES];
+	struct {
+		u64		addr;
+		struct symbol	*symbol;
+	} last_find_result[MAP__NR_TYPES];
 	void		 *a2l;
 	char		 *symsrc_filename;
 	unsigned int	 a2l_fails;
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 45c2e3a..725640f 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -444,7 +444,12 @@ static struct symbol *symbols__find_by_name(struct rb_root *symbols,
 struct symbol *dso__find_symbol(struct dso *dso,
 				enum map_type type, u64 addr)
 {
-	return symbols__find(&dso->symbols[type], addr);
+	if (dso->last_find_result[type].addr != addr) {
+		dso->last_find_result[type].addr   = addr;
+		dso->last_find_result[type].symbol = symbols__find(&dso->symbols[type], addr);
+	}
+
+	return dso->last_find_result[type].symbol;
 }
 
 struct symbol *dso__first_symbol(struct dso *dso, enum map_type type)