Re: [PATCH -tip 6/7] perf bts trace: print function+offset

Masami Hiramatsu
2010-12-06T03:20:38Z

(2010/12/03 13:00), Akihiro Nagai wrote:
> Provide the function to print function+offset.
> And, set it as the default behavior of 'perf bts trace'.
> To use this function, users can also specify the option '-s' or '--symbol'.
>
> Example: 'perf bts -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
> ...
>
> Signed-off-by: Akihiro Nagai <akihiro.nagai.hw@hitachi.com>

You might think the next step is displaying line number of the address.
Feel free to use/update probe-finder.c :)

Reviewed-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>

> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Paul Mackerras <paulus@samba.org>
> Cc: Ingo Molnar <mingo@elte.hu>
> Cc: Arnaldo Carvalho de Melo <acme@ghostprotocols.net>
> Cc: linux-kernel@vger.kernel.org
> ---
>
> tools/perf/Documentation/perf-bts.txt | 5 +++-
> tools/perf/builtin-bts.c | 44 ++++++++++++++++++++++++++++++---
> 2 files changed, 44 insertions(+), 5 deletions(-)
>
> diff --git a/tools/perf/Documentation/perf-bts.txt b/tools/perf/Documentation/perf-bts.txt
> index acabffc..13ee862 100644
> --- a/tools/perf/Documentation/perf-bts.txt
> +++ b/tools/perf/Documentation/perf-bts.txt
> @@ -31,7 +31,7 @@ OPTIONS
> Specify input file name to analyze.
> -a::
> --addr::
> - Print address. (default)
> + Print address.
> -c::
> --comm::
> Print command name.
> @@ -41,6 +41,9 @@ 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-bts.c b/tools/perf/builtin-bts.c
> index 3b2a21e..71c7fbe 100644
> --- a/tools/perf/builtin-bts.c
> +++ b/tools/perf/builtin-bts.c
> @@ -21,6 +21,8 @@ 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
> @@ -30,9 +32,10 @@ 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;
> @@ -43,6 +46,9 @@ static unsigned long print_flags;
> #define EI_UNKNOWN_TEXT "(unknown)"
> #define EI_UNKNOWN_TEXT_LEN (sizeof(EI_UNKNOWN_TEXT))
>
> +/* 'function+offset' lengh = function + '+' + %#18llx + '\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";
>
> @@ -71,7 +77,7 @@ static int set_print_flags(const struct option *opt, const char *str __unused,
> static const struct option bts_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,
> @@ -82,6 +88,10 @@ static const struct option bts_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()
> };
>
> @@ -106,7 +116,7 @@ static void fill_exec_info(struct exec_info *ei, struct perf_session *session,
> 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);
> @@ -115,8 +125,14 @@ static void fill_exec_info(struct exec_info *ei, struct perf_session *session,
> MAP__FUNCTION, event->ip.pid, addr, &al);
> if (!al.map)
> return;
> - map__load(al.map, NULL);
> +
> + al.addr = al.map->map_ip(al.map, addr);
> + al.sym = map__find_symbol(al.map, al.addr, NULL);
> + if (!al.sym)
> + return;
> ei->elfpath = al.map->dso->long_name;
> + ei->function = al.sym->name;
> + ei->offset = al.addr - al.sym->start;
> }
>
> static void __print_exec_info(struct exec_info *ei)
> @@ -124,6 +140,8 @@ 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)
> @@ -138,6 +156,22 @@ 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%llx",
> + 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);
> @@ -160,6 +194,8 @@ 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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--
Masami HIRAMATSU
2nd Dept. Linux Technology Center
Hitachi, Ltd., Systems Development Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com