[PATCH v6 0/5] perf report: Show inline stack

[Jin Yao]

v6:
Ravi reported a build error that was:

util/srcline.c: In function âaddr2inlinesâ:
util/srcline.c:403:7: error: too few arguments to function âinline_list__appendâ
   if (inline_list__append(filename, NULL, line_nr, node) != 0)
       ^
util/srcline.c:34:12: note: declared here
 static int inline_list__append(char *filename, char *funcname, int line_nr,
            ^
util/srcline.c: At top level:
util/srcline.c:60:13: error: âinline_list__reverseâ defined but not used [-Werror=unused-function]
 static void inline_list__reverse(struct inline_node *node)
             ^
cc1: all warnings being treated as errors
mv: cannot stat âutil/.srcline.o.tmpâ: No such file or directory

The error happens when BFD lib is not enabled in build environment.
The patch series should be improved for better compatibility for this case.

So in v6, these patches are changed.

  perf report: Find the inline stack for a given address
  perf report: Show inline stack for stdio mode
  perf report: Show inline stack for browser mode

Without BFD, the inlined function name is not supported even "-g function" set.
It's only filename:line_nr printing.

Following patches are not changed.

  perf report: Refactor common code in srcline.c
  perf report: Create new inline option

v5: Update according to Milian Wolff's comments. It groups by address
    (then display file/ line), or by function (then display function name).

    For example:

    1. Show inlined function name
       perf report --stdio -g function --inline

       0.69%     0.00%  inline   ld-2.23.so           [.] dl_main
              |
              ---dl_main
                 |
                  --0.56%--_dl_relocate_object
                           _dl_relocate_object (inline)
                           elf_dynamic_do_Rela (inline)

     2. Show the file/line information
        perf report --stdio -g address --inline

        0.69%     0.00%  inline   ld-2.23.so           [.] _dl_start_user
              |
              ---_dl_start_user .:0
                 _dl_start rtld.c:307
                 /build/glibc-GKVZIf/glibc-2.23/elf/rtld.c:413 (inline)
                 _dl_sysdep_start dl-sysdep.c:250
                 |
                  --0.56%--dl_main rtld.c:2076

    2 patches are updated according to this change.
    perf report: Show inline stack in browser mode
    perf report: Show inline stack in stdio mode

    3 patches are not changed.
    perf report: Find the inline stack for a given address
    perf report: Refactor common code in srcline.c
    perf report: Create new inline option

v4: Remove the options "--inline-line" and "--inline-name". Just use
    a new option "--inline" to print the inline function information.
    The policy is if the inline function name can be resolved then
    print the name in priority. If the name can't be resolved, then
    print the source line number.

    For example:
    perf report --stdio --inline

    0.69%     0.00%  inline   ld-2.23.so           [.] dl_main
           |
           ---dl_main
              |
               --0.56%--_dl_relocate_object
                         |
                         ---_dl_relocate_object (inline)
                            elf_dynamic_do_Rela (inline)

    Following 3 patches are updated according to this change.
    perf report: Show inline stack in browser mode
    perf report: Show inline stack in stdio mode
    perf report: Create new inline option

    Following are not changed.
    perf report: Find the inline stack for a given address
    perf report: Refactor common code in srcline.c

v3: Iterate on RIPs of all callchain entries to check if the RIP is in
    inline functions.

    Reverse the order of the inliner printout if necessary.

    Provide new options "--inline-line" / "--inline-name" to print
    inline function name or print inline function source line.

v2: Thanks so much for Arnaldo's comments!
    The modifications are:

    1. Divide v1 patch "perf report: Find the inline stack for a
       given address" into 2 patches:
       a. perf report: Refactor common code in srcline.c
       b. perf report: Find the inline stack for a given address

       Some function names are changed:
       dso_name_get -> dso__name
       ilist_apend -> inline_list__append
       get_inline_node -> dso__parse_addr_inlines
       free_inline_node -> inline_node__delete

    2. Since the function name are changed, update following patches
       accordingly.
       a. perf report: Show inline stack in stdio mode
       b. perf report: Show inline stack in browser mode

    3. Rebase to latest perf/core branch. This patch is impacted.
       a. perf report: Create a new option "--inline"

v1: Initial post

It would be useful for perf to support a mode to query the
inline stack for callgraph addresses. This would simplify
finding the right code in code that does a lot of inlining.

For example, the c code:

static inline void f3(void)
{
        int i;
        for (i = 0; i < 1000;) {

                if(i%2)
                        i++;
                else
                        i++;
        }
        printf("hello f3\n");   /* D */
}

/* < CALLCHAIN: f2 <- f1 > */
static inline void f2(void)
{
        int i;
        for (i = 0; i < 100; i++) {
                f3();   /* C */
        }
}

/* < CALLCHAIN: f1 <- main > */
static inline void f1(void)
{
        int i;
        for (i = 0; i < 100; i++) {
                f2();   /* B */
        }
}

/* < CALLCHAIN: main <- TOP > */
int main()
{
        struct timeval tv;
        time_t start, end;

        gettimeofday(&tv, NULL);
        start = end = tv.tv_sec;
        while((end - start) < 5) {
                f1();   /* A */
                gettimeofday(&tv, NULL);
                end = tv.tv_sec;
        }
        return 0;
}

The printed inline stack is:

0.05%  test2    test2              [.] main
       |
       ---/home/perf-dev/lck-2867/test/test2.c:27 (inline)
          /home/perf-dev/lck-2867/test/test2.c:35 (inline)
          /home/perf-dev/lck-2867/test/test2.c:45 (inline)
          /home/perf-dev/lck-2867/test/test2.c:61 (inline)

I tag A/B/C/D in above c code to indicate the source line,
actually the inline stack is equal to:

0.05%  test2    test2              [.] main
       |
       ---D
          C
          B
          A

Jin Yao (5):
  perf report: Refactor common code in srcline.c
  perf report: Find the inline stack for a given address
  perf report: Introduce --inline option
  perf report: Show inline stack for stdio mode
  perf report: Show inline stack for browser mode

 tools/perf/Documentation/perf-report.txt |   4 +
 tools/perf/builtin-report.c              |   2 +
 tools/perf/ui/browsers/hists.c           | 180 +++++++++++++++++++++--
 tools/perf/ui/stdio/hist.c               |  85 ++++++++++-
 tools/perf/util/hist.c                   |   5 +
 tools/perf/util/sort.h                   |   1 +
 tools/perf/util/srcline.c                | 235 +++++++++++++++++++++++++++----
 tools/perf/util/symbol-elf.c             |   5 +
 tools/perf/util/symbol-minimal.c         |   7 +
 tools/perf/util/symbol.h                 |   5 +-
 tools/perf/util/util.h                   |  16 +++
 11 files changed, 507 insertions(+), 38 deletions(-)

-- 
2.7.4