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Commit 7dbf4dcf authored by Jiri Olsa's avatar Jiri Olsa Committed by Arnaldo Carvalho de Melo
Browse files

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: default avatarJiri Olsa <jolsa@redhat.com>
Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
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: default avatarArnaldo Carvalho de Melo <acme@redhat.com>
parent 1c4be9ff

tools/perf/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -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

tools/perf/builtin-buildid-cache.c

+2 −1
Original line number Diff line number Diff line
@@ -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");

tools/perf/util/header.c

+49 −21
Original line number Diff line number Diff line
@@ -21,6 +21,7 @@ 
#include "debug.h"

#include "cpumap.h"

#include "pmu.h"

#include "vdso.h"



static bool no_buildid_cache = false;
@@ -207,31 +208,53 @@ perf_header__set_cmdline(int argc, const char **argv) 
			continue;		\

		else



static int __dsos__write_buildid_table(struct list_head *head, pid_t pid,

				u16 misc, int fd)

static int write_buildid(char *name, size_t name_len, u8 *build_id,

			 pid_t pid, u16 misc, int fd)

{

	struct dso *pos;



	dsos__for_each_with_build_id(pos, head) {

	int err;

	struct build_id_event b;

	size_t len;



		if (!pos->hit)

			continue;

		len = pos->long_name_len + 1;

	len = 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));

	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;

		err = write_padded(fd, pos->long_name,

				   pos->long_name_len + 1, len);

		if (err < 0)



	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)

{

	struct dso *pos;



	dsos__for_each_with_build_id(pos, head) {

		int err;

		char  *name;

		size_t name_len;



		if (!pos->hit)

			continue;



		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;

	}
@@ -277,12 +300,13 @@ 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) {
@@ -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 @@ int build_id_cache__add_s(const char *sbuild_id, const char *debugdir, 


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 @@ int build_id_cache__remove_s(const char *sbuild_id, const char *debugdir) 
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)

tools/perf/util/header.h

+1 −1
Original line number Diff line number Diff line
@@ -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,

tools/perf/util/map.c

+9 −3
Original line number Diff line number Diff line
@@ -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;

		}



		if (vdso) {

			pgoff = 0;

			dso = vdso__dso_findnew(dsos__list);

		} else

			dso = __dsos__findnew(dsos__list, filename);



		if (dso == NULL)

			goto out_delete;