perf annotate browser: Display titles in left frame

The annotate browser is divided into 2 frames. Left frame contains 3
columns (some platforms only have one column).

For example:

                   │26  int compute_flag()
                   │27  {
 22.80  1.20       │      sub    $0x8,%rsp
                   │25          int i;
                   │
                   │27          i = rand() % 2;
 22.78  1.20     1 │    → callq  rand@plt

While it's hard for user to understand what the data is.

This patch adds the titles "Percent", "IPC" and "Cycle" on columns.

Percent  IPC Cycle │
                   │25  __attribute__((noinline))
                   │26  int compute_flag()
                   │27  {
 22.80  1.20       │      sub    $0x8,%rsp
                   │25          int i;
                   │
                   │27          i = rand() % 2;
 22.78  1.20     1 │    → callq  rand@plt

The titles are displayed at row 0 of annotate browser if row 0 doesn't
have values of percent, ipc and cycle.
Signed-off-by: Yao Jin <yao.jin@linux.intel.com>
Acked-by: Milian Wolff <milian.wolff@kdab.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Yao Jin <yao.jin@linux.intel.com>
Link: http://lkml.kernel.org/r/1493909895-9668-3-git-send-email-yao.jin@linux.intel.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/ui/browsers/annotate.c

@@ -125,12 +125,21 @@ static void annotate_browser__write(struct ui_browser *browser, void *entry, int
 	int i, pcnt_width = annotate_browser__pcnt_width(ab);
 	double percent_max = 0.0;
 	char bf[256];
+	bool show_title = false;
 
 	for (i = 0; i < ab->nr_events; i++) {
 		if (bdl->samples[i].percent > percent_max)
 			percent_max = bdl->samples[i].percent;
 	}
 
+	if ((row == 0) && (dl->offset == -1 || percent_max == 0.0)) {
+		if (ab->have_cycles) {
+			if (dl->ipc == 0.0 && dl->cycles == 0)
+				show_title = true;
+		} else
+			show_title = true;
+	}
+
 	if (dl->offset != -1 && percent_max != 0.0) {
 		for (i = 0; i < ab->nr_events; i++) {
 			ui_browser__set_percent_color(browser,
@@ -146,18 +155,27 @@ static void annotate_browser__write(struct ui_browser *browser, void *entry, int
 		}
 	} else {
 		ui_browser__set_percent_color(browser, 0, current_entry);
+
+		if (!show_title)
 			ui_browser__write_nstring(browser, " ", 7 * ab->nr_events);
+		else
+			ui_browser__printf(browser, "%*s", 7, "Percent");
 	}
 	if (ab->have_cycles) {
 		if (dl->ipc)
 			ui_browser__printf(browser, "%*.2f ", IPC_WIDTH - 1, dl->ipc);
-		else
+		else if (!show_title)
 			ui_browser__write_nstring(browser, " ", IPC_WIDTH);
+		else
+			ui_browser__printf(browser, "%*s ", IPC_WIDTH - 1, "IPC");
+
 		if (dl->cycles)
 			ui_browser__printf(browser, "%*" PRIu64 " ",
 					   CYCLES_WIDTH - 1, dl->cycles);
-		else
+		else if (!show_title)
 			ui_browser__write_nstring(browser, " ", CYCLES_WIDTH);
+		else
+			ui_browser__printf(browser, "%*s ", CYCLES_WIDTH - 1, "Cycle");
 	}
 
 	SLsmg_write_char(' ');