From 1ae14516cba032a83b561144d3d48fd381584c0c Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Wed, 13 Nov 2019 16:33:33 -0300 Subject: [PATCH] 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 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 Cc: Andi Kleen Cc: Jiri Olsa Cc: Namhyung Kim Link: https://lkml.kernel.org/n/tip-tcz37g3nxv3tvxw3q90vga3p@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- 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 49e353eaa337..d0899df77baa 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 26fc68bd4f60..f2a3158572eb 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 0fb9bd8bcf0d..b146d87176e7 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;