The following commit has been merged into the perf/core branch of tip:
Commit-ID: 1ae14516cba032a83b561144d3d48fd381584c0c
Gitweb: https://git.kernel.org/tip/1ae14516cba032a83b561144d3d48fd381584c0c
Author: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
AuthorDate: Wed, 13 Nov 2019 16:33:33 -03:00
Committer: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
CommitterDate: Mon, 18 Nov 2019 11:21:32 -03:00
perf map_groups: Add a front end cache for map lookups by name
Lets see if it helps:
First look at the probeable lines for the function that does lookups by
name in a map_groups struct:
# perf probe -x ~/bin/perf -L map_groups__find_by_name
<map_groups__find_by_name@/home/acme/git/perf/tools/perf/util/symbol.c:0>
0 struct map *map_groups__find_by_name(struct map_groups *mg, const char *name)
1 {
2 struct maps *maps = &mg->maps;
struct map *map;
5 down_read(&maps->lock);
7 if (mg->last_search_by_name && strcmp(mg->last_search_by_name->dso->short_name, name) == 0) {
8 map = mg->last_search_by_name;
9 goto out_unlock;
}
12 maps__for_each_entry(maps, map)
13 if (strcmp(map->dso->short_name, name) == 0) {
14 mg->last_search_by_name = map;
15 goto out_unlock;
}
18 map = NULL;
out_unlock:
21 up_read(&maps->lock);
22 return map;
23 }
int dso__load_vmlinux(struct dso *dso, struct map *map,
const char *vmlinux, bool vmlinux_allocated)
#
Now add a probe to the place where we reuse the last search:
# perf probe -x ~/bin/perf map_groups__find_by_name:8
Added new event:
probe_perf:map_groups__find_by_name (on map_groups__find_by_name:8 in /home/acme/bin/perf)
You can now use it in all perf tools, such as:
perf record -e probe_perf:map_groups__find_by_name -aR sleep 1
#
Now lets do a system wide 'perf stat' counting those events:
# perf stat -e probe_perf:*
Leave it running and lets do a 'perf top', then, after a while, stop the
'perf stat':
# perf stat -e probe_perf:*
^C
Performance counter stats for 'system wide':
3,603 probe_perf:map_groups__find_by_name
44.565253139 seconds time elapsed
#
yeah, good to have.
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Link: https://lkml.kernel.org/n/tip-tcz37g3nxv3tvxw3q90vga3p@xxxxxxxxxxxxxx
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/util/map.c | 9 +++++++++
tools/perf/util/map_groups.h | 6 ++----
tools/perf/util/symbol.c | 9 ++++++++-
3 files changed, 19 insertions(+), 5 deletions(-)
diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index 49e353e..d0899df 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -572,6 +572,7 @@ void map_groups__init(struct map_groups *mg, struct machine *machine)
{
maps__init(&mg->maps);
mg->machine = machine;
+ mg->last_search_by_name = NULL;
refcount_set(&mg->refcnt, 1);
}
@@ -580,6 +581,14 @@ void map_groups__insert(struct map_groups *mg, struct map *map)
maps__insert(&mg->maps, map);
}
+void map_groups__remove(struct map_groups *mg, struct map *map)
+{
+ if (mg->last_search_by_name == map)
+ mg->last_search_by_name = NULL;
+
+ maps__remove(&mg->maps, map);
+}
+
static void __maps__purge(struct maps *maps)
{
struct map *pos, *next;
diff --git a/tools/perf/util/map_groups.h b/tools/perf/util/map_groups.h
index 26fc68b..f2a3158 100644
--- a/tools/perf/util/map_groups.h
+++ b/tools/perf/util/map_groups.h
@@ -36,6 +36,7 @@ struct symbol *maps__find_symbol_by_name(struct maps *maps, const char *name, st
struct map_groups {
struct maps maps;
struct machine *machine;
+ struct map *last_search_by_name;
refcount_t refcnt;
#ifdef HAVE_LIBUNWIND_SUPPORT
void *addr_space;
@@ -70,10 +71,7 @@ size_t map_groups__fprintf(struct map_groups *mg, FILE *fp);
void map_groups__insert(struct map_groups *mg, struct map *map);
-static inline void map_groups__remove(struct map_groups *mg, struct map *map)
-{
- maps__remove(&mg->maps, map);
-}
+void map_groups__remove(struct map_groups *mg, struct map *map);
static inline struct map *map_groups__find(struct map_groups *mg, u64 addr)
{
diff --git a/tools/perf/util/symbol.c b/tools/perf/util/symbol.c
index 0fb9bd8..b146d87 100644
--- a/tools/perf/util/symbol.c
+++ b/tools/perf/util/symbol.c
@@ -1767,9 +1767,16 @@ struct map *map_groups__find_by_name(struct map_groups *mg, const char *name)
down_read(&maps->lock);
+ if (mg->last_search_by_name && strcmp(mg->last_search_by_name->dso->short_name, name) == 0) {
+ map = mg->last_search_by_name;
+ goto out_unlock;
+ }
+
maps__for_each_entry(maps, map)
- if (strcmp(map->dso->short_name, name) == 0)
+ if (strcmp(map->dso->short_name, name) == 0) {
+ mg->last_search_by_name = map;
goto out_unlock;
+ }
map = NULL;
|