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Subject[PATCH -tip v3 5/6] perf branch trace: print function+offset
Date
Provide the function to print function+offset.
And, set it as the default behavior of 'perf branch trace'.
To use this function, users can also specify the option '-s' or '--symbol'.

Example: 'perf branch -as trace'
This command prints address and function+offset.

Output sample:
address function+offset
0xffffffff8146fe0e irq_return+0x0 => 0x00007fd4038e3b20 _start+0x0
...
0x000000380661ee79 __libc_start_main+0xf9 => 0x00000000004035c3 main+0x0
0xffffffff8146ef4e irq_return+0x0 => 0x00000000004035c3 main+0x0
0x00000000004035e8 main+0x25 => 0x000000000040bca0 set_program_name+0x0
0xffffffff8146ef4e irq_return+0x0 => 0x000000000040bca0 set_program_name+0x0
0x000000000040bcae set_program_name+0xe => 0x00000000004023d0 strrchr@plt+0x0
0x00000000004023d0 strrchr@plt+0x0 => 0x00000000004023d6 strrchr@plt+0x6
...
0x0000000000403e0c main+0x849 => 0x00000000004021f0 exit@plt+0x0
0x00000000004021f0 exit@plt+0x0 => 0x00000000004021f6 exit@plt+0x6
0x00000000004021fb exit@plt+0xb => 0x00000000004020d0 _init+0x18
0x00000000004020d6 _init+0x1e => 0x00000038062149d0 _dl_runtime_resolve+0x0
...
Changes in V3:
- rename to 'perf branch'
- fix getting elf_path bug

Signed-off-by: Akihiro Nagai <akihiro.nagai.hw@hitachi.com>
Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
---
tools/perf/Documentation/perf-branch.txt | 5 +++
tools/perf/builtin-branch.c | 43 ++++++++++++++++++++++++++++--
2 files changed, 44 insertions(+), 4 deletions(-)
diff --git a/tools/perf/Documentation/perf-branch.txt b/tools/perf/Documentation/perf-branch.txt
index f98b32e..9c7e100 100644
--- a/tools/perf/Documentation/perf-branch.txt
+++ b/tools/perf/Documentation/perf-branch.txt
@@ -32,7 +32,7 @@ OPTIONS
Specify input file name to analyze.
-a::
--addr::
- Print address. (default)
+ Print address.
-c::
--comm::
Print command name.
@@ -42,6 +42,9 @@ OPTIONS
-e::
--elfpath::
Print file path of executed elf.
+-s::
+--symbol::
+ Print function name and offset. (default)

SEE ALSO
--------
diff --git a/tools/perf/builtin-branch.c b/tools/perf/builtin-branch.c
index 3d8a9c5..819443e 100644
--- a/tools/perf/builtin-branch.c
+++ b/tools/perf/builtin-branch.c
@@ -23,6 +23,8 @@ struct exec_info {
pid_t pid; /* tracee process pid */
const char *comm; /* command name */
const char *elfpath; /* file path to elf */
+ const char *function; /* function name */
+ u64 offset; /* offset from top of the function */
};

#define EI_PID_UNSET -1
@@ -32,9 +34,10 @@ struct exec_info {
#define EI_FLAG_PRINT_PID (1 << 1)
#define EI_FLAG_PRINT_COMM (1 << 2)
#define EI_FLAG_PRINT_ELFPATH (1 << 3)
+#define EI_FLAG_PRINT_SYMBOL (1 << 4)

/* it's used when no print item specified */
-#define EI_FLAG_PRINT_DEFAULT EI_FLAG_PRINT_ADDR
+#define EI_FLAG_PRINT_DEFAULT EI_FLAG_PRINT_SYMBOL

/* print item flags */
static unsigned long print_flags;
@@ -45,6 +48,9 @@ static unsigned long print_flags;
#define EI_UNKNOWN_TEXT "(unknown)"
#define EI_UNKNOWN_TEXT_LEN (sizeof(EI_UNKNOWN_TEXT))

+/* 'function+offset' lengh = function + '+' + %#18lx + '\0' */
+#define symbol_buf_size(func_name) (strlen(func_name) + 1 + 18 + 1)
+
/* default input file name to analyze */
static const char *input_name = "perf.data";

@@ -73,7 +79,7 @@ static int set_print_flags(const struct option *opt, const char *str __unused,
static const struct option branch_options[] = {
OPT_STRING('i', "input", &input_name, "file", "input file name"),
OPT_CALLBACK_DEFAULT_NOOPT('a', "addr", NULL, NULL,
- "print address (default)", set_print_flags,
+ "print address", set_print_flags,
(void *)EI_FLAG_PRINT_ADDR),
OPT_CALLBACK_DEFAULT_NOOPT('p', "pid", NULL, NULL,
"print pid", set_print_flags,
@@ -84,6 +90,10 @@ static const struct option branch_options[] = {
OPT_CALLBACK_DEFAULT_NOOPT('e', "elfpath", NULL, NULL,
"print file path to elf", set_print_flags,
(void *)EI_FLAG_PRINT_ELFPATH),
+ OPT_CALLBACK_DEFAULT_NOOPT('s', "symbol", NULL, NULL,
+ "print function+offset (default)",
+ set_print_flags,
+ (void *)EI_FLAG_PRINT_SYMBOL),
OPT_END()
};

@@ -129,7 +139,7 @@ static void fill_exec_info(struct exec_info *ei,
return;
ei->comm = thread->comm;

- /* get file path to elf */
+ /* get file path to elf, and symbol information */
memset(&al, 0, sizeof(al));
thread__find_addr_map(thread, session, PERF_RECORD_MISC_USER,
MAP__FUNCTION, event->ip.pid, addr, &al);
@@ -141,6 +151,13 @@ static void fill_exec_info(struct exec_info *ei,
/* resolve vmlinux path */
map__load(al.map, NULL);
ei->elfpath = al.map->dso->long_name;
+
+ al.addr = al.map->map_ip(al.map, addr);
+ al.sym = map__find_symbol(al.map, al.addr, NULL);
+ if (!al.sym)
+ return;
+ ei->function = al.sym->name;
+ ei->offset = al.addr - al.sym->start;
}

static void __print_exec_info(struct exec_info *ei)
@@ -148,6 +165,8 @@ static void __print_exec_info(struct exec_info *ei)
char pid[16];
const char *comm;
const char *elfpath;
+ char *symbol;
+ int symbol_len;

if (print_flags & EI_FLAG_PRINT_PID) {
if (ei->pid == EI_PID_UNSET)
@@ -162,6 +181,22 @@ static void __print_exec_info(struct exec_info *ei)
}
if (print_flags & EI_FLAG_PRINT_ADDR)
printf(FMT_ADDR " ", ei->addr);
+ if (print_flags & EI_FLAG_PRINT_SYMBOL) {
+ if (!ei->function) {
+ /* when function is unknown, offset must be unknown */
+ printf("%-32s ", EI_UNKNOWN_TEXT);
+ goto print_elfpath;
+ }
+
+ symbol_len = symbol_buf_size(ei->function);
+ symbol = malloc(symbol_len);
+ snprintf(symbol, symbol_len, "%s+0x%lx",
+ ei->function, ei->offset);
+ printf("%-32s ", symbol);
+ free(symbol);
+ }
+
+print_elfpath:
if (print_flags & EI_FLAG_PRINT_ELFPATH) {
elfpath = ei->elfpath ? : EI_UNKNOWN_TEXT;
printf("%-32s ", elfpath);
@@ -184,6 +219,8 @@ static void print_exec_info_header(void)
printf("%-12s ", "command");
if (print_flags & EI_FLAG_PRINT_ADDR)
printf("%-" FMT_ADDR_WIDTH "s ", "address");
+ if (print_flags & EI_FLAG_PRINT_SYMBOL)
+ printf("%-32s ", "function+offset");
if (print_flags & EI_FLAG_PRINT_ELFPATH)
printf("%-32s ", "elf_filepath");
printf("\n");


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