[PATCH v4 3/5] perf tools: Fix dynamic sort keys to sort properly

[Namhyung Kim <namhyung@kernel.org>]

Currently, the dynamic sort keys compares trace data using memcmp().
But for output sorting, it should check data size and compare by word.
Also it sorted strings in reverse order, fix it.

Before)

  $ perf report -F overhead -s prev_pid,next_pid
  ...
  # Overhead    prev_pid    next_pid
  # ........  ..........  ..........
  #
       0.39%         490           0
       9.12%         225           0
       0.04%         224           0
       0.51%         731         189
       0.08%         731           3
       0.12%         731           0
       4.82%         729           0
       0.08%        1229           0
       0.20%         715           0
       4.78%         189         225
  ...

After)

  $ perf report -F overhead -s prev_pid,next_pid
  ...
  # Overhead    prev_pid    next_pid
  # ........  ..........  ..........
  #
       0.43%           0           7
       0.04%           0          11
       0.04%           0          12
       0.08%           0          14
       0.04%           0          17
       0.08%           0          19
       0.04%           0          22
       0.04%           0          27
       0.04%           0          37
       0.04%           0          42
  ...

Reported-by: Arnaldo Carvalho de Melo <acme@kernel.org>
Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
 tools/perf/util/sort.c | 23 ++++++++++++++++++++++-
 1 file changed, 22 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c
index e8a5cdee3f0d..4d05b13aeac8 100644
--- a/tools/perf/util/sort.c
+++ b/tools/perf/util/sort.c
@@ -1804,6 +1804,9 @@ static int64_t __sort__hde_sort(struct perf_hpp_fmt *fmt,
 	struct hpp_dynamic_entry *hde;
 	struct format_field *field;
 	unsigned offset, size;
+	int64_t *a64, *b64;
+	int32_t *a32, *b32;
+	int16_t *a16, *b16;
 
 	hde = container_of(fmt, struct hpp_dynamic_entry, hpp);
 
@@ -1819,7 +1822,25 @@ static int64_t __sort__hde_sort(struct perf_hpp_fmt *fmt,
 		size = field->size;
 	}
 
-	return memcmp(b->raw_data + offset, a->raw_data + offset, size);
+	if (field->flags & FIELD_IS_STRING)
+		return strcmp(b->raw_data + offset, a->raw_data + offset);
+
+	switch (size) {
+	case 8:
+		a64 = a->raw_data + offset;
+		b64 = b->raw_data + offset;
+		return *b64 - *a64;
+	case 4:
+		a32 = a->raw_data + offset;
+		b32 = b->raw_data + offset;
+		return *b32 - *a32;
+	case 2:
+		a16 = a->raw_data + offset;
+		b16 = b->raw_data + offset;
+		return *b16 - *a16;
+	default:
+		return memcmp(b->raw_data + offset, a->raw_data + offset, size);
+	}
 }
 
 bool perf_hpp__is_dynamic_entry(struct perf_hpp_fmt *fmt)
-- 
2.6.4