perf annotate-data: Add stack operation pseudo type

A typical function prologue and epilogue include multiple stack
operations to save and restore the current value of registers.
On x86, it looks like below:

  push  r15
  push  r14
  push  r13
  push  r12

  ...

  pop   r12
  pop   r13
  pop   r14
  pop   r15
  ret

As these all touches the stack memory region, chances are high that they
appear in a memory profile data.  But these are not used for any real
purpose yet so it'd return no types.

One of my profile type shows that non neglible portion of data came from
the stack operations.  It also seems GCC generates more stack operations
than clang.

Annotate Instruction stats
total 264, ok 169 (64.0%), bad 95 (36.0%)

    Name      :  Good   Bad
  -----------------------------------------------------------
    movq      :    49    27
    movl      :    24     9
    popq      :     0    19   <-- here
    cmpl      :    17     2
    addq      :    14     1
    cmpq      :    12     2
    cmpxchgl  :     3     7

Instead of dealing them as unknown, let's create a seperate pseudo type
to represent those stack operations separately.

Reviewed-by: Ian Rogers <irogers@google.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20240117062657.985479-5-namhyung@kernel.org
Signed-off-by: Namhyung Kim <namhyung@kernel.org>

diff --git a/tools/perf/util/annotate-data.h b/tools/perf/util/annotate-data.h
index 65ddd839850f306990aa72745550a4b49b20ecc9..214c625e7bc96c0995272536baeea36ef78eca58 100644 (file)
--- a/tools/perf/util/annotate-data.h
+++ b/tools/perf/util/annotate-data.h
@@ -70,6 +70,7 @@ struct annotated_data_type {
 };
 
 extern struct annotated_data_type unknown_type;
+extern struct annotated_data_type stackop_type;
 
 /**
  * struct annotated_data_stat - Debug statistics

diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index 3cdcdd449c86595e765cb7dc7e4c8a719d42a71a..655bd9443f5e9b78ee0fa00154ca681ec7bab3d5 100644 (file)
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -107,6 +107,14 @@ static struct ins_ops ret_ops;
 struct annotated_data_stat ann_data_stat;
 LIST_HEAD(ann_insn_stat);
 
+/* Pseudo data types */
+struct annotated_data_type stackop_type = {
+       .self = {
+               .type_name = (char *)"(stack operation)",
+               .children = LIST_HEAD_INIT(stackop_type.self.children),
+       },
+};
+
 static int arch__grow_instructions(struct arch *arch)
 {
        struct ins *new_instructions;
@@ -3724,6 +3732,18 @@ static struct annotated_item_stat *annotate_data_stat(struct list_head *head,
        return istat;
 }
 
+static bool is_stack_operation(struct arch *arch, struct disasm_line *dl)
+{
+       if (arch__is(arch, "x86")) {
+               if (!strncmp(dl->ins.name, "push", 4) ||
+                   !strncmp(dl->ins.name, "pop", 3) ||
+                   !strncmp(dl->ins.name, "ret", 3))
+                       return true;
+       }
+
+       return false;
+}
+
 /**
  * hist_entry__get_data_type - find data type for given hist entry
  * @he: hist entry
@@ -3789,6 +3809,12 @@ retry:
                return NULL;
        }
 
+       if (is_stack_operation(arch, dl)) {
+               istat->good++;
+               he->mem_type_off = 0;
+               return &stackop_type;
+       }
+
        for_each_insn_op_loc(&loc, i, op_loc) {
                if (!op_loc->mem_ref)
                        continue;