1 files changed, 41 insertions, 1 deletions

diff --git a/tools/perf/builtin-top.c b/tools/perf/builtin-top.c
index 6613f988a33e..3af95203208a 100644
--- a/tools/perf/builtin-top.c
+++ b/tools/perf/builtin-top.c
@@ -60,7 +60,7 @@ static int			system_wide			=      0;
 static int                      default_interval                =      0;
 
 static int                      count_filter                    =      5;
-static int                      print_entries                   =     15;
+static int                      print_entries;
 
 static int                      target_pid                      =     -1;
 static int                      inherit                         =      0;
@@ -115,6 +115,36 @@ struct sym_entry {
  * Source functions
  */
 
+/* most GUI terminals set LINES (although some don't export it) */
+static int term_rows(void)
+{
+        char *lines_string = getenv("LINES");
+        int n_lines;
+
+        if (lines_string && (n_lines = atoi(lines_string)) > 0)
+                return n_lines;
+#ifdef TIOCGWINSZ
+        else {
+                struct winsize ws;
+                if (!ioctl(1, TIOCGWINSZ, &ws) && ws.ws_row)
+                        return ws.ws_row;
+        }
+#endif
+        return 25;
+}
+
+static void update_print_entries(void)
+{
+        print_entries = term_rows();
+        if (print_entries > 9)
+                print_entries -= 9;
+}
+
+static void sig_winch_handler(int sig __used)
+{
+        update_print_entries();
+}
+
 static void parse_source(struct sym_entry *syme)
 {
         struct symbol *sym;
@@ -668,6 +698,11 @@ static void handle_keypress(int c)
                         break;
                 case 'e':
                         prompt_integer(&print_entries, "Enter display entries (lines)");
+                        if (print_entries == 0) {
+                                update_print_entries();
+                                signal(SIGWINCH, sig_winch_handler);
+                        } else
+                                signal(SIGWINCH, SIG_DFL);
                         break;
                 case 'E':
                         if (nr_counters > 1) {
@@ -1228,5 +1263,10 @@ int cmd_top(int argc, const char **argv, const char *prefix __used)
         if (target_pid != -1 || profile_cpu != -1)
                 nr_cpus = 1;
 
+        if (print_entries == 0) {
+                update_print_entries();
+                signal(SIGWINCH, sig_winch_handler);
+        }
+
         return __cmd_top();
 }