perf inject: Do not load map/dso when injecting build-id

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 25 -> 21 msec on my laptop.
Also the memory usage (Max RSS) went down by ~200 KB.

  # Running 'internals/inject-build-id' benchmark:
    Average build-id injection took: 21.389 msec (+- 0.138 msec)
    Average time per event: 2.097 usec (+- 0.014 usec)
    Average memory usage: 8225 KB (+- 0 KB)

Committer notes:

Before:

  $ perf stat -r5 perf bench internals inject-build-id > /dev/null

   Performance counter stats for 'perf bench internals inject-build-id' (5 runs):

            4,020.56 msec task-clock:u              #    1.271 CPUs utilized            ( +-  0.74% )
                   0      context-switches:u        #    0.000 K/sec
                   0      cpu-migrations:u          #    0.000 K/sec
             123,354      page-faults:u             #    0.031 M/sec                    ( +-  0.81% )
       7,119,951,568      cycles:u                  #    1.771 GHz                      ( +-  1.74% )  (83.27%)
         230,086,969      stalled-cycles-frontend:u #    3.23% frontend cycles idle     ( +-  1.97% )  (83.41%)
       1,168,298,765      stalled-cycles-backend:u  #   16.41% backend cycles idle      ( +-  1.13% )  (83.44%)
      11,173,083,669      instructions:u            #    1.57  insn per cycle
                                                    #    0.10  stalled cycles per insn  ( +-  1.58% )  (83.31%)
       2,413,908,936      branches:u                #  600.392 M/sec                    ( +-  1.69% )  (83.26%)
          46,576,289      branch-misses:u           #    1.93% of all branches          ( +-  2.20% )  (83.31%)

              3.1638 +- 0.0309 seconds time elapsed  ( +-  0.98% )

  $

After:

  $ perf stat -r5 perf bench internals inject-build-id > /dev/null

   Performance counter stats for 'perf bench internals inject-build-id' (5 runs):

            2,379.94 msec task-clock:u              #    1.473 CPUs utilized            ( +-  0.18% )
                   0      context-switches:u        #    0.000 K/sec
                   0      cpu-migrations:u          #    0.000 K/sec
              62,584      page-faults:u             #    0.026 M/sec                    ( +-  0.07% )
       2,372,389,668      cycles:u                  #    0.997 GHz                      ( +-  0.29% )  (83.14%)
         106,937,862      stalled-cycles-frontend:u #    4.51% frontend cycles idle     ( +-  4.89% )  (83.20%)
         581,697,915      stalled-cycles-backend:u  #   24.52% backend cycles idle      ( +-  0.71% )  (83.47%)
       3,659,692,199      instructions:u            #    1.54  insn per cycle
                                                    #    0.16  stalled cycles per insn  ( +-  0.10% )  (83.63%)
         791,372,961      branches:u                #  332.518 M/sec                    ( +-  0.27% )  (83.39%)
          10,648,083      branch-misses:u           #    1.35% of all branches          ( +-  0.22% )  (83.16%)

             1.61570 +- 0.00172 seconds time elapsed  ( +-  0.11% )

  $

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Original-patch-by: Stephane Eranian <eranian@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Link: https://lore.kernel.org/r/20201012070214.2074921-5-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 1 insertions, 16 deletions

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;