From 7dbf4dcfe2987c35c2c4675cd7ae1b6006979176 Mon Sep 17 00:00:00 2001 From: Jiri Olsa Date: Mon, 10 Sep 2012 18:50:19 +0200 Subject: perf tools: Back [vdso] DSO with real data Storing data for VDSO shared object, because we need it for the post unwind processing. The VDSO shared object is same for all process on a running system, so it makes no difference when we store it inside the tracer - perf. When [vdso] map memory is hit, we retrieve [vdso] DSO image and store it into temporary file. During the build-id processing phase, the [vdso] DSO image is stored in build-id db, and build-id reference is made inside perf.data. The build-id vdso file object is called '[vdso]'. We don't use temporary file name which gets removed when record is finished. During report phase the vdso build-id object is treated as any other build-id DSO object. Adding following API for vdso object: bool is_vdso_map(const char *filename) - returns true if the filename matches vdso map name struct dso *vdso__dso_findnew(struct list_head *head) - find/create proper vdso DSO object vdso__exit(void) - removes temporary VDSO image if there's any This change makes backtrace dwarf post unwind possible from [vdso] maps. Following output is current report of [vdso] sample dwarf backtrace: # Overhead Command Shared Object Symbol # ........ ....... ................. ............................. # 99.52% ex [vdso] [.] 0x00007fff3ace89af | --- 0x7fff3ace89af Following output is new report of [vdso] sample dwarf backtrace: # Overhead Command Shared Object Symbol # ........ ....... ................. ............................. # 99.52% ex [vdso] [.] 0x00000000000009af | --- 0x7fff3ace89af main __libc_start_main _start Signed-off-by: Jiri Olsa Acked-by: Peter Zijlstra Cc: Frederic Weisbecker Cc: Ingo Molnar Cc: Paul Mackerras Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1347295819-23177-5-git-send-email-jolsa@redhat.com [ committer note: s/ALIGN/PERF_ALIGN/g to cope with the android build changes ] Signed-off-by: Arnaldo Carvalho de Melo diff --git a/tools/perf/Makefile b/tools/perf/Makefile index 1d2723c..209774b 100644 --- a/tools/perf/Makefile +++ b/tools/perf/Makefile @@ -337,6 +337,7 @@ LIB_H += util/intlist.h LIB_H += util/perf_regs.h LIB_H += util/unwind.h LIB_H += ui/helpline.h +LIB_H += util/vdso.h LIB_OBJS += $(OUTPUT)util/abspath.o LIB_OBJS += $(OUTPUT)util/alias.o @@ -404,6 +405,7 @@ LIB_OBJS += $(OUTPUT)util/cgroup.o LIB_OBJS += $(OUTPUT)util/target.o LIB_OBJS += $(OUTPUT)util/rblist.o LIB_OBJS += $(OUTPUT)util/intlist.o +LIB_OBJS += $(OUTPUT)util/vdso.o LIB_OBJS += $(OUTPUT)ui/helpline.o LIB_OBJS += $(OUTPUT)ui/hist.o diff --git a/tools/perf/builtin-buildid-cache.c b/tools/perf/builtin-buildid-cache.c index 29ad20e..995368e 100644 --- a/tools/perf/builtin-buildid-cache.c +++ b/tools/perf/builtin-buildid-cache.c @@ -43,7 +43,8 @@ static int build_id_cache__add_file(const char *filename, const char *debugdir) } build_id__sprintf(build_id, sizeof(build_id), sbuild_id); - err = build_id_cache__add_s(sbuild_id, debugdir, filename, false); + err = build_id_cache__add_s(sbuild_id, debugdir, filename, + false, false); if (verbose) pr_info("Adding %s %s: %s\n", sbuild_id, filename, err ? "FAIL" : "Ok"); diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index 974e758..87996ca 100644 --- a/tools/perf/util/header.c +++ b/tools/perf/util/header.c @@ -21,6 +21,7 @@ #include "debug.h" #include "cpumap.h" #include "pmu.h" +#include "vdso.h" static bool no_buildid_cache = false; @@ -207,6 +208,29 @@ perf_header__set_cmdline(int argc, const char **argv) continue; \ else +static int write_buildid(char *name, size_t name_len, u8 *build_id, + pid_t pid, u16 misc, int fd) +{ + int err; + struct build_id_event b; + size_t len; + + len = name_len + 1; + len = PERF_ALIGN(len, NAME_ALIGN); + + memset(&b, 0, sizeof(b)); + memcpy(&b.build_id, build_id, BUILD_ID_SIZE); + b.pid = pid; + b.header.misc = misc; + b.header.size = sizeof(b) + len; + + err = do_write(fd, &b, sizeof(b)); + if (err < 0) + return err; + + return write_padded(fd, name, name_len + 1, len); +} + static int __dsos__write_buildid_table(struct list_head *head, pid_t pid, u16 misc, int fd) { @@ -214,24 +238,23 @@ static int __dsos__write_buildid_table(struct list_head *head, pid_t pid, dsos__for_each_with_build_id(pos, head) { int err; - struct build_id_event b; - size_t len; + char *name; + size_t name_len; if (!pos->hit) continue; - len = pos->long_name_len + 1; - len = PERF_ALIGN(len, NAME_ALIGN); - memset(&b, 0, sizeof(b)); - memcpy(&b.build_id, pos->build_id, sizeof(pos->build_id)); - b.pid = pid; - b.header.misc = misc; - b.header.size = sizeof(b) + len; - err = do_write(fd, &b, sizeof(b)); - if (err < 0) - return err; - err = write_padded(fd, pos->long_name, - pos->long_name_len + 1, len); - if (err < 0) + + if (is_vdso_map(pos->short_name)) { + name = (char *) VDSO__MAP_NAME; + name_len = sizeof(VDSO__MAP_NAME) + 1; + } else { + name = pos->long_name; + name_len = pos->long_name_len + 1; + } + + err = write_buildid(name, name_len, pos->build_id, + pid, misc, fd); + if (err) return err; } @@ -277,19 +300,20 @@ static int dsos__write_buildid_table(struct perf_header *header, int fd) } int build_id_cache__add_s(const char *sbuild_id, const char *debugdir, - const char *name, bool is_kallsyms) + const char *name, bool is_kallsyms, bool is_vdso) { const size_t size = PATH_MAX; char *realname, *filename = zalloc(size), *linkname = zalloc(size), *targetname; int len, err = -1; + bool slash = is_kallsyms || is_vdso; if (is_kallsyms) { if (symbol_conf.kptr_restrict) { pr_debug("Not caching a kptr_restrict'ed /proc/kallsyms\n"); return 0; } - realname = (char *)name; + realname = (char *) name; } else realname = realpath(name, NULL); @@ -297,7 +321,8 @@ int build_id_cache__add_s(const char *sbuild_id, const char *debugdir, goto out_free; len = scnprintf(filename, size, "%s%s%s", - debugdir, is_kallsyms ? "/" : "", realname); + debugdir, slash ? "/" : "", + is_vdso ? VDSO__MAP_NAME : realname); if (mkdir_p(filename, 0755)) goto out_free; @@ -333,13 +358,14 @@ out_free: static int build_id_cache__add_b(const u8 *build_id, size_t build_id_size, const char *name, const char *debugdir, - bool is_kallsyms) + bool is_kallsyms, bool is_vdso) { char sbuild_id[BUILD_ID_SIZE * 2 + 1]; build_id__sprintf(build_id, build_id_size, sbuild_id); - return build_id_cache__add_s(sbuild_id, debugdir, name, is_kallsyms); + return build_id_cache__add_s(sbuild_id, debugdir, name, + is_kallsyms, is_vdso); } int build_id_cache__remove_s(const char *sbuild_id, const char *debugdir) @@ -383,9 +409,11 @@ out_free: static int dso__cache_build_id(struct dso *dso, const char *debugdir) { bool is_kallsyms = dso->kernel && dso->long_name[0] != '/'; + bool is_vdso = is_vdso_map(dso->short_name); return build_id_cache__add_b(dso->build_id, sizeof(dso->build_id), - dso->long_name, debugdir, is_kallsyms); + dso->long_name, debugdir, + is_kallsyms, is_vdso); } static int __dsos__cache_build_ids(struct list_head *head, const char *debugdir) diff --git a/tools/perf/util/header.h b/tools/perf/util/header.h index 9d5eedc..209dad4 100644 --- a/tools/perf/util/header.h +++ b/tools/perf/util/header.h @@ -96,7 +96,7 @@ int perf_header__process_sections(struct perf_header *header, int fd, int perf_header__fprintf_info(struct perf_session *s, FILE *fp, bool full); int build_id_cache__add_s(const char *sbuild_id, const char *debugdir, - const char *name, bool is_kallsyms); + const char *name, bool is_kallsyms, bool is_vdso); int build_id_cache__remove_s(const char *sbuild_id, const char *debugdir); int perf_event__synthesize_attr(struct perf_tool *tool, diff --git a/tools/perf/util/map.c b/tools/perf/util/map.c index 7d37159..b442ee4 100644 --- a/tools/perf/util/map.c +++ b/tools/perf/util/map.c @@ -9,6 +9,7 @@ #include "map.h" #include "thread.h" #include "strlist.h" +#include "vdso.h" const char *map_type__name[MAP__NR_TYPES] = { [MAP__FUNCTION] = "Functions", @@ -23,7 +24,6 @@ static inline int is_anon_memory(const char *filename) static inline int is_no_dso_memory(const char *filename) { return !strcmp(filename, "[stack]") || - !strcmp(filename, "[vdso]") || !strcmp(filename, "[heap]"); } @@ -52,9 +52,10 @@ struct map *map__new(struct list_head *dsos__list, u64 start, u64 len, if (self != NULL) { char newfilename[PATH_MAX]; struct dso *dso; - int anon, no_dso; + int anon, no_dso, vdso; anon = is_anon_memory(filename); + vdso = is_vdso_map(filename); no_dso = is_no_dso_memory(filename); if (anon) { @@ -62,7 +63,12 @@ struct map *map__new(struct list_head *dsos__list, u64 start, u64 len, filename = newfilename; } - dso = __dsos__findnew(dsos__list, filename); + if (vdso) { + pgoff = 0; + dso = vdso__dso_findnew(dsos__list); + } else + dso = __dsos__findnew(dsos__list, filename); + if (dso == NULL) goto out_delete; diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c index 0ecd62b..e0fd6c7 100644 --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -17,6 +17,7 @@ #include "event-parse.h" #include "perf_regs.h" #include "unwind.h" +#include "vdso.h" static int perf_session__open(struct perf_session *self, bool force) { @@ -211,6 +212,7 @@ void perf_session__delete(struct perf_session *self) machine__exit(&self->host_machine); close(self->fd); free(self); + vdso__exit(); } void machine__remove_thread(struct machine *self, struct thread *th) diff --git a/tools/perf/util/vdso.c b/tools/perf/util/vdso.c new file mode 100644 index 0000000..e60951f --- /dev/null +++ b/tools/perf/util/vdso.c @@ -0,0 +1,111 @@ + +#include +#include +#include +#include +#include +#include +#include +#include + +#include "vdso.h" +#include "util.h" +#include "symbol.h" +#include "linux/string.h" + +static bool vdso_found; +static char vdso_file[] = "/tmp/perf-vdso.so-XXXXXX"; + +static int find_vdso_map(void **start, void **end) +{ + FILE *maps; + char line[128]; + int found = 0; + + maps = fopen("/proc/self/maps", "r"); + if (!maps) { + pr_err("vdso: cannot open maps\n"); + return -1; + } + + while (!found && fgets(line, sizeof(line), maps)) { + int m = -1; + + /* We care only about private r-x mappings. */ + if (2 != sscanf(line, "%p-%p r-xp %*x %*x:%*x %*u %n", + start, end, &m)) + continue; + if (m < 0) + continue; + + if (!strncmp(&line[m], VDSO__MAP_NAME, + sizeof(VDSO__MAP_NAME) - 1)) + found = 1; + } + + fclose(maps); + return !found; +} + +static char *get_file(void) +{ + char *vdso = NULL; + char *buf = NULL; + void *start, *end; + size_t size; + int fd; + + if (vdso_found) + return vdso_file; + + if (find_vdso_map(&start, &end)) + return NULL; + + size = end - start; + + buf = memdup(start, size); + if (!buf) + return NULL; + + fd = mkstemp(vdso_file); + if (fd < 0) + goto out; + + if (size == (size_t) write(fd, buf, size)) + vdso = vdso_file; + + close(fd); + + out: + free(buf); + + vdso_found = (vdso != NULL); + return vdso; +} + +void vdso__exit(void) +{ + if (vdso_found) + unlink(vdso_file); +} + +struct dso *vdso__dso_findnew(struct list_head *head) +{ + struct dso *dso = dsos__find(head, VDSO__MAP_NAME); + + if (!dso) { + char *file; + + file = get_file(); + if (!file) + return NULL; + + dso = dso__new(VDSO__MAP_NAME); + if (dso != NULL) { + dsos__add(head, dso); + dso__set_long_name(dso, file); + } + } + + return dso; +} diff --git a/tools/perf/util/vdso.h b/tools/perf/util/vdso.h new file mode 100644 index 0000000..0f76e7c --- /dev/null +++ b/tools/perf/util/vdso.h @@ -0,0 +1,18 @@ +#ifndef __PERF_VDSO__ +#define __PERF_VDSO__ + +#include +#include +#include + +#define VDSO__MAP_NAME "[vdso]" + +static inline bool is_vdso_map(const char *filename) +{ + return !strcmp(filename, VDSO__MAP_NAME); +} + +struct dso *vdso__dso_findnew(struct list_head *head); +void vdso__exit(void); + +#endif /* __PERF_VDSO__ */ -- cgit v0.10.2