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 --- tools/perf/util/header.c | 70 +++++++++++++++++++++++++++++++++--------------- 1 file changed, 49 insertions(+), 21 deletions(-) (limited to 'tools/perf/util/header.c') diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c index 974e7589a6b5..87996cab21d0 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) -- cgit v1.2.3-59-g8ed1b