perf annotate: Fix annotate context lines regression

The live annotation done in 'perf top' needs to limit the context before
lines that aren't filtered out by the min percent filter, if we don't do
that, the screen in a tty often is not enough for showing what is
interesting: lines with hits and a few source code lines before it.

Reported-by: Mike Galbraith <efault@gmx.de>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Tom Zanussi <tzanussi@gmail.com>
LKML-Reference: <new-submission>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-top.c

@@ -231,7 +231,7 @@ static void show_details(struct sym_entry *syme)
 	printf("  Events  Pcnt (>=%d%%)\n", sym_pcnt_filter);
 
 	more = symbol__annotate_printf(symbol, syme->map, top.sym_evsel->idx,
-				       0, sym_pcnt_filter, top.print_entries);
+				       0, sym_pcnt_filter, top.print_entries, 4);
 	if (top.zero)
 		symbol__annotate_zero_histogram(symbol, top.sym_evsel->idx);
 	else

tools/perf/util/annotate.c

@@ -111,7 +111,8 @@ struct objdump_line *objdump__get_next_ip_line(struct list_head *head,
 
 static int objdump_line__print(struct objdump_line *oline, struct symbol *sym,
 			       int evidx, u64 len, int min_pcnt,
-			       int printed, int max_lines)
+			       int printed, int max_lines,
+			       struct objdump_line *queue)
 {
 	static const char *prev_line;
 	static const char *prev_color;
@@ -150,6 +151,15 @@ static int objdump_line__print(struct objdump_line *oline, struct symbol *sym,
 		if (max_lines && printed >= max_lines)
 			return 1;
 
+		if (queue != NULL) {
+			list_for_each_entry_from(queue, &notes->src->source, node) {
+				if (queue == oline)
+					break;
+				objdump_line__print(queue, sym, evidx, len,
+						    0, 0, 1, NULL);
+			}
+		}
+
 		color = get_percent_color(percent);
 
 		/*
@@ -172,6 +182,9 @@ static int objdump_line__print(struct objdump_line *oline, struct symbol *sym,
 	} else if (max_lines && printed >= max_lines)
 		return 1;
 	else {
+		if (queue)
+			return -1;
+
 		if (!*oline->line)
 			printf("         :\n");
 		else
@@ -452,13 +465,14 @@ static void symbol__annotate_hits(struct symbol *sym, int evidx)
 }
 
 int symbol__annotate_printf(struct symbol *sym, struct map *map, int evidx,
-			    bool full_paths, int min_pcnt, int max_lines)
+			    bool full_paths, int min_pcnt, int max_lines,
+			    int context)
 {
 	struct dso *dso = map->dso;
 	const char *filename = dso->long_name, *d_filename;
 	struct annotation *notes = symbol__annotation(sym);
-	struct objdump_line *pos;
-	int printed = 2;
+	struct objdump_line *pos, *queue = NULL;
+	int printed = 2, queue_len = 0;
 	int more = 0;
 	u64 len;
 
@@ -476,18 +490,37 @@ int symbol__annotate_printf(struct symbol *sym, struct map *map, int evidx,
 		symbol__annotate_hits(sym, evidx);
 
 	list_for_each_entry(pos, &notes->src->source, node) {
+		if (context && queue == NULL) {
+			queue = pos;
+			queue_len = 0;
+		}
+
 		switch (objdump_line__print(pos, sym, evidx, len, min_pcnt,
-					    printed, max_lines)) {
+					    printed, max_lines, queue)) {
 		case 0:
 			++printed;
+			if (context) {
+				printed += queue_len;
+				queue = NULL;
+				queue_len = 0;
+			}
 			break;
 		case 1:
 			/* filtered by max_lines */
 			++more;
 			break;
 		case -1:
 		default:
-			/* filtered by min_pcnt */
+			/*
+			 * Filtered by min_pcnt or non IP lines when
+			 * context != 0
+			 */
+			if (!context)
+				break;
+			if (queue_len == context)
+				queue = list_entry(queue->node.next, typeof(*queue), node);
+			else
+				++queue_len;
 			break;
 		}
 	}
@@ -550,7 +583,7 @@ int symbol__tty_annotate(struct symbol *sym, struct map *map, int evidx,
 	}
 
 	symbol__annotate_printf(sym, map, evidx, full_paths,
-				min_pcnt, max_lines);
+				min_pcnt, max_lines, 0);
 	if (print_lines)
 		symbol__free_source_line(sym, len);
 

tools/perf/util/annotate.h

@@ -78,7 +78,8 @@ void symbol__annotate_zero_histograms(struct symbol *sym);
 int symbol__annotate(struct symbol *sym, struct map *map, size_t privsize);
 int symbol__annotate_init(struct map *map __used, struct symbol *sym);
 int symbol__annotate_printf(struct symbol *sym, struct map *map, int evidx,
-			    bool full_paths, int min_pcnt, int max_lines);
+			    bool full_paths, int min_pcnt, int max_lines,
+			    int context);
 void symbol__annotate_zero_histogram(struct symbol *sym, int evidx);
 void symbol__annotate_decay_histogram(struct symbol *sym, int evidx);
 void objdump_line_list__purge(struct list_head *head);