knotty: Show task elapsed time

Its often useful to know how long a task has been running for. This patch adds that information to the task display, updating every 5s if there were no other updates so the user can see how long tasks have been running for.

[YOCTO #9737]

index a1856ec..c34b6f6 100644
@@ -170,6 +170,7 @@ class TerminalFilter(object):

         self.interactive = sys.stdout.isatty()
         self.footer_present = False
         self.lastpids = []
+        self.lasttime = None
         self.quiet = quiet

         if not self.interactive:
@@ -226,6 +227,10 @@ class TerminalFilter(object):
         activetasks = self.helper.running_tasks
         failedtasks = self.helper.failed_tasks
         runningpids = self.helper.running_pids
+        currenttime = time.time()
+        if not self.lasttime or (currenttime - self.lasttime > 5):
+            self.helper.needUpdate = True
+            self.lasttime = currenttime
         if self.footer_present and not self.helper.needUpdate:
             return
         self.helper.needUpdate = False
@@ -250,7 +256,11 @@ class TerminalFilter(object):
                     activetasks[t]["progressbar"] = pbar
                 tasks.append((pbar, progress, rate, start_time))
             else:
-                tasks.append("%s (pid %s)" % (activetasks[t]["title"], t))
+                start_time = activetasks[t].get("starttime", None)
+                if start_time:
+                    tasks.append("%s - %ds (pid %s)" % (activetasks[t]["title"], currenttime - start_time, t)) +                else:
+                    tasks.append("%s (pid %s)" % (activetasks[t]["title"], t))

         if self.main.shutdown:
             content = "Waiting for %s running tasks to finish:" % len(activetasks)