[PATCH v2 1/3] perf annotate: Compute average IPC and IPC coverage per symbol

[Jin Yao]

Add support to perf report annotate view or perf annotate --stdio2 to
aggregate the IPC derived from timed LBRs per symbol. We compute the
average IPC and the IPC coverage percentage.

For example,

$ perf annotate --stdio2

Percent  IPC Cycle (Average IPC: 2.30, IPC Coverage: 54.8%)

                        Disassembly of section .text:

                        000000000003aac0 <random@@GLIBC_2.2.5>:
  8.32  3.28              sub    $0x18,%rsp
        3.28              mov    $0x1,%esi
        3.28              xor    %eax,%eax
        3.28              cmpl   $0x0,argp_program_version_hook@@GLIBC_2.2.5+0x1e0
 11.57  3.28     1      â je     20
                          lock   cmpxchg %esi,__abort_msg@@GLIBC_PRIVATE+0x8a0
                        â jne    29
                        â jmp    43
 11.57  1.10        20:   cmpxchg %esi,__abort_msg@@GLIBC_PRIVATE+0x8a0
  0.00  1.10     1      â je     43
                    29:   lea    __abort_msg@@GLIBC_PRIVATE+0x8a0,%rdi
                          sub    $0x80,%rsp
                        â callq  __lll_lock_wait_private
                          add    $0x80,%rsp
  0.00  3.00        43:   lea    __ctype_b@xxxxxxxxxxx+0x38,%rdi
        3.00              lea    0xc(%rsp),%rsi
  8.49  3.00     1      â callq  __random_r
  7.91  1.94              cmpl   $0x0,argp_program_version_hook@@GLIBC_2.2.5+0x1e0
  0.00  1.94     1      â je     68
                          lock   decl   __abort_msg@@GLIBC_PRIVATE+0x8a0
                        â jne    70
                        â jmp    8a
  0.00  2.00        68:   decl   __abort_msg@@GLIBC_PRIVATE+0x8a0
 21.56  2.00     1      â je     8a
                    70:   lea    __abort_msg@@GLIBC_PRIVATE+0x8a0,%rdi
                          sub    $0x80,%rsp
                        â callq  __lll_unlock_wake_private
                          add    $0x80,%rsp
 21.56  2.90        8a:   movslq 0xc(%rsp),%rax
        2.90              add    $0x18,%rsp
  9.03  2.90     1      â retq

It shows for this symbol the average IPC is 2.30 and the IPC coverage
is 54.8%.

Signed-off-by: Jin Yao <yao.jin@xxxxxxxxxxxxxxx>
---
 tools/perf/util/annotate.c | 41 ++++++++++++++++++++++++++++++++++++++---
 tools/perf/util/annotate.h |  5 +++++
 2 files changed, 43 insertions(+), 3 deletions(-)

diff --git a/tools/perf/util/annotate.c b/tools/perf/util/annotate.c
index 6936daf..4b2b1b0 100644
--- a/tools/perf/util/annotate.c
+++ b/tools/perf/util/annotate.c
@@ -1000,6 +1000,7 @@ static unsigned annotation__count_insn(struct annotation *notes, u64 start, u64
 static void annotation__count_and_fill(struct annotation *notes, u64 start, u64 end, struct cyc_hist *ch)
 {
 	unsigned n_insn;
+	unsigned int cover_insn = 0;
 	u64 offset;
 
 	n_insn = annotation__count_insn(notes, start, end);
@@ -1013,21 +1014,34 @@ static void annotation__count_and_fill(struct annotation *notes, u64 start, u64
 		for (offset = start; offset <= end; offset++) {
 			struct annotation_line *al = notes->offsets[offset];
 
-			if (al)
+			if (al && al->ipc == 0.0) {
 				al->ipc = ipc;
+				cover_insn++;
+			}
+		}
+
+		if (cover_insn) {
+			notes->hit_cycles += ch->cycles;
+			notes->hit_insn += n_insn * ch->num;
+			notes->cover_insn += cover_insn;
 		}
 	}
 }
 
 void annotation__compute_ipc(struct annotation *notes, size_t size)
 {
-	u64 offset;
+	s64 offset;
 
 	if (!notes->src || !notes->src->cycles_hist)
 		return;
 
+	notes->total_insn = annotation__count_insn(notes, 0, size - 1);
+	notes->hit_cycles = 0;
+	notes->hit_insn = 0;
+	notes->cover_insn = 0;
+
 	pthread_mutex_lock(&notes->lock);
-	for (offset = 0; offset < size; ++offset) {
+	for (offset = size - 1; offset >= 0; --offset) {
 		struct cyc_hist *ch;
 
 		ch = &notes->src->cycles_hist[offset];
@@ -2563,6 +2577,22 @@ static void disasm_line__write(struct disasm_line *dl, struct annotation *notes,
 	disasm_line__scnprintf(dl, bf, size, !notes->options->use_offset);
 }
 
+static void ipc_coverage_string(char *bf, int size, struct annotation *notes)
+{
+	double ipc = 0.0, coverage = 0.0;
+
+	if (notes->hit_cycles)
+		ipc = notes->hit_insn / ((double)notes->hit_cycles);
+
+	if (notes->total_insn) {
+		coverage = notes->cover_insn * 100.0 /
+			((double)notes->total_insn);
+	}
+
+	scnprintf(bf, size, "(Average IPC: %.2f, IPC Coverage: %.1f%%)",
+		  ipc, coverage);
+}
+
 static void __annotation_line__write(struct annotation_line *al, struct annotation *notes,
 				     bool first_line, bool current_entry, bool change_color, int width,
 				     void *obj, unsigned int percent_type,
@@ -2658,6 +2688,11 @@ static void __annotation_line__write(struct annotation_line *al, struct annotati
 					    ANNOTATION__MINMAX_CYCLES_WIDTH - 1,
 					    "Cycle(min/max)");
 		}
+
+		if (show_title && !*al->line) {
+			ipc_coverage_string(bf, sizeof(bf), notes);
+			obj__printf(obj, "%*s", ANNOTATION__AVG_IPC_WIDTH, bf);
+		}
 	}
 
 	obj__printf(obj, " ");
diff --git a/tools/perf/util/annotate.h b/tools/perf/util/annotate.h
index 5399ba2..fb64637 100644
--- a/tools/perf/util/annotate.h
+++ b/tools/perf/util/annotate.h
@@ -64,6 +64,7 @@ bool ins__is_fused(struct arch *arch, const char *ins1, const char *ins2);
 #define ANNOTATION__IPC_WIDTH 6
 #define ANNOTATION__CYCLES_WIDTH 6
 #define ANNOTATION__MINMAX_CYCLES_WIDTH 19
+#define ANNOTATION__AVG_IPC_WIDTH 36
 
 struct annotation_options {
 	bool hide_src_code,
@@ -262,6 +263,10 @@ struct annotation {
 	pthread_mutex_t		lock;
 	u64			max_coverage;
 	u64			start;
+	u64			hit_cycles;
+	u64			hit_insn;
+	unsigned int		total_insn;
+	unsigned int		cover_insn;
 	struct annotation_options *options;
 	struct annotation_line	**offsets;
 	int			nr_events;
-- 
2.7.4