[PATCH 4/6] perf inject: Do not load map/dso when injecting build-id

From: Namhyung Kim
Date: Mon Sep 28 2020 - 03:53:22 EST


No need to load symbols in a DSO when injecting build-id. I guess the
reason was to check the DSO is a special file like anon files. Use
some helper functions in map.c to check them before reading build-id.
Also pass sample event's cpumode to a new build-id event.

It brought a speedup in the benchmark of 23 -> 18 msec on my laptop.
Also the memory usage (Max RSS) went down by ~400 KB.

# Running 'internals/inject-build-id' benchmark:
Average build-id injection took: 18.153 msec (+- 0.073 msec)
Average time per event: 1.780 usec (+- 0.007 usec)
Average memory usage: 7431 KB (+- 6 KB)

Original-patch-by: Stephane Eranian <eranian@xxxxxxxxxx>
Acked-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Signed-off-by: Namhyung Kim <namhyung@xxxxxxxxxx>
---
tools/perf/builtin-inject.c | 33 ++++++++++++---------------------
tools/perf/util/map.c | 17 +----------------
tools/perf/util/map.h | 14 ++++++++++++++
3 files changed, 27 insertions(+), 37 deletions(-)

diff --git a/tools/perf/builtin-inject.c b/tools/perf/builtin-inject.c
index 670157db2502..248cd9f3e5bb 100644
--- a/tools/perf/builtin-inject.c
+++ b/tools/perf/builtin-inject.c
@@ -24,9 +24,10 @@
#include "util/synthetic-events.h"
#include "util/thread.h"
#include "util/namespaces.h"
-#include <linux/err.h>

+#include <linux/err.h>
#include <subcmd/parse-options.h>
+#include <uapi/linux/mman.h> /* To get things like MAP_HUGETLB even on older libc headers */

#include <linux/list.h>
#include <errno.h>
@@ -436,21 +437,22 @@ static int dso__read_build_id(struct dso *dso)
}

static int dso__inject_build_id(struct dso *dso, struct perf_tool *tool,
- struct machine *machine)
+ struct machine *machine, u8 cpumode, u32 flags)
{
- u16 misc = PERF_RECORD_MISC_USER;
int err;

+ if (is_anon_memory(dso->long_name) || flags & MAP_HUGETLB)
+ return 0;
+ if (is_no_dso_memory(dso->long_name))
+ return 0;
+
if (dso__read_build_id(dso) < 0) {
pr_debug("no build_id found for %s\n", dso->long_name);
return -1;
}

- if (dso->kernel)
- misc = PERF_RECORD_MISC_KERNEL;
-
- err = perf_event__synthesize_build_id(tool, dso, misc, perf_event__repipe,
- machine);
+ err = perf_event__synthesize_build_id(tool, dso, cpumode,
+ perf_event__repipe, machine);
if (err) {
pr_err("Can't synthesize build_id event for %s\n", dso->long_name);
return -1;
@@ -477,19 +479,8 @@ int perf_event__inject_buildid(struct perf_tool *tool, union perf_event *event,
if (thread__find_map(thread, sample->cpumode, sample->ip, &al)) {
if (!al.map->dso->hit) {
al.map->dso->hit = 1;
- if (map__load(al.map) >= 0) {
- dso__inject_build_id(al.map->dso, tool, machine);
- /*
- * If this fails, too bad, let the other side
- * account this as unresolved.
- */
- } else {
-#ifdef HAVE_LIBELF_SUPPORT
- pr_warning("no symbols found in %s, maybe "
- "install a debug package?\n",
- al.map->dso->long_name);
-#endif
- }
+ dso__inject_build_id(al.map->dso, tool, machine,
+ sample->cpumode, al.map->flags);
}
}

diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c
index cc0faf8f1321..8b305e624124 100644
--- a/tools/perf/util/map.c
+++ b/tools/perf/util/map.c
@@ -27,21 +27,6 @@

static void __maps__insert(struct maps *maps, struct map *map);

-static inline int is_anon_memory(const char *filename, u32 flags)
-{
- return flags & MAP_HUGETLB ||
- !strcmp(filename, "//anon") ||
- !strncmp(filename, "/dev/zero", sizeof("/dev/zero") - 1) ||
- !strncmp(filename, "/anon_hugepage", sizeof("/anon_hugepage") - 1);
-}
-
-static inline int is_no_dso_memory(const char *filename)
-{
- return !strncmp(filename, "[stack", 6) ||
- !strncmp(filename, "/SYSV",5) ||
- !strcmp(filename, "[heap]");
-}
-
static inline int is_android_lib(const char *filename)
{
return strstarts(filename, "/data/app-lib/") ||
@@ -158,7 +143,7 @@ struct map *map__new(struct machine *machine, u64 start, u64 len,
int anon, no_dso, vdso, android;

android = is_android_lib(filename);
- anon = is_anon_memory(filename, flags);
+ anon = is_anon_memory(filename) || flags & MAP_HUGETLB;
vdso = is_vdso_map(filename);
no_dso = is_no_dso_memory(filename);
map->prot = prot;
diff --git a/tools/perf/util/map.h b/tools/perf/util/map.h
index c2f5d28fe73a..b1c0686db1b7 100644
--- a/tools/perf/util/map.h
+++ b/tools/perf/util/map.h
@@ -171,4 +171,18 @@ static inline bool is_bpf_image(const char *name)
return strncmp(name, "bpf_trampoline_", sizeof("bpf_trampoline_") - 1) == 0 ||
strncmp(name, "bpf_dispatcher_", sizeof("bpf_dispatcher_") - 1) == 0;
}
+
+static inline int is_anon_memory(const char *filename)
+{
+ return !strcmp(filename, "//anon") ||
+ !strncmp(filename, "/dev/zero", sizeof("/dev/zero") - 1) ||
+ !strncmp(filename, "/anon_hugepage", sizeof("/anon_hugepage") - 1);
+}
+
+static inline int is_no_dso_memory(const char *filename)
+{
+ return !strncmp(filename, "[stack", 6) ||
+ !strncmp(filename, "/SYSV", 5) ||
+ !strcmp(filename, "[heap]");
+}
#endif /* __PERF_MAP_H */
--
2.28.0.681.g6f77f65b4e-goog