stack: Add some trace instrumentation

The stack and stack tracker tend to cause missed frames from time to
time, especially when there are many open windows. Add some
instrumentation to make it this easily verifiable when profiling.

Part-of: <https://gitlab.gnome.org/GNOME/mutter/-/merge_requests/1616>

2 files changed, 20 insertions, 0 deletions

diff --git a/src/core/stack-tracker.c b/src/core/stack-tracker.c
index a1f8e709d..11a1f0707 100644
--- a/src/core/stack-tracker.c
+++ b/src/core/stack-tracker.c
@@ -1185,9 +1185,13 @@ meta_stack_tracker_restack_managed (MetaStackTracker *tracker,
   int n_windows;
   int old_pos, new_pos;
 
+  COGL_TRACE_BEGIN_SCOPED (StackTrackerRestackManaged,
+                           "StackTracker: Restack Managed");
   if (n_managed == 0)
     return;
 
+  COGL_TRACE_BEGIN (StackTrackerRestackManagedGet,
+                    "StackTracker: Restack Managed (get)");
   meta_stack_tracker_get_stack (tracker, &windows, &n_windows);
 
   /* If the top window has to be restacked, we don't want to move it to the very
@@ -1204,7 +1208,10 @@ meta_stack_tracker_restack_managed (MetaStackTracker *tracker,
         break;
     }
   g_assert (old_pos >= 0);
+  COGL_TRACE_END (StackTrackerRestackManagedGet);
 
+  COGL_TRACE_BEGIN (StackTrackerRestackManagedRaise,
+                    "StackTracker: Restack Managed (raise)");
   new_pos = n_managed - 1;
   if (managed[new_pos] != windows[old_pos])
     {
@@ -1213,10 +1220,13 @@ meta_stack_tracker_restack_managed (MetaStackTracker *tracker,
       meta_stack_tracker_get_stack (tracker, &windows, &n_windows);
       /* Moving managed[new_pos] above windows[old_pos], moves the window at old_pos down by one */
     }
+  COGL_TRACE_END (StackTrackerRestackManagedRaise);
 
   old_pos--;
   new_pos--;
 
+  COGL_TRACE_BEGIN (StackTrackerRestackManagedRestack,
+                    "StackTracker: Restack Managed (restack)");
   while (old_pos >= 0 && new_pos >= 0)
     {
       if (meta_stack_tracker_is_guard_window (tracker, windows[old_pos]))
@@ -1243,12 +1253,16 @@ meta_stack_tracker_restack_managed (MetaStackTracker *tracker,
       old_pos--;
       new_pos--;
     }
+  COGL_TRACE_END (StackTrackerRestackManagedRestack);
 
+  COGL_TRACE_BEGIN (StackTrackerRestackManagedLower,
+                    "StackTracker: Restack Managed (lower)");
   while (new_pos > 0)
     {
       meta_stack_tracker_lower_below (tracker, managed[new_pos], managed[new_pos - 1]);
       new_pos--;
     }
+  COGL_TRACE_END (StackTrackerRestackManagedLower);
 }
 
 void
@@ -1260,6 +1274,8 @@ meta_stack_tracker_restack_at_bottom (MetaStackTracker *tracker,
   int n_windows;
   int pos;
 
+  COGL_TRACE_BEGIN_SCOPED (StackTrackerRestackAtBottom,
+                           "Stack tracker: Restack at bottom");
   meta_stack_tracker_get_stack (tracker, &windows, &n_windows);
 
   for (pos = 0; pos < n_new_order; pos++)
diff --git a/src/core/stack.c b/src/core/stack.c
index 44dce7098..e1e73867d 100644
--- a/src/core/stack.c
+++ b/src/core/stack.c
@@ -78,6 +78,8 @@ on_stack_changed (MetaStack *stack)
   GArray *hidden_stack_ids;
   GList *sorted;
 
+  COGL_TRACE_BEGIN_SCOPED (StackChanged, "Stack changed");
+
   meta_topic (META_DEBUG_STACK, "Syncing window stack to server");
 
   all_root_children_stacked = g_array_new (FALSE, FALSE, sizeof (uint64_t));
@@ -259,6 +261,8 @@ meta_stack_changed (MetaStack *stack)
   if (stack->freeze_count > 0)
     return;
 
+  COGL_TRACE_BEGIN_SCOPED (MetaStackChangedSort, "Stack: Changed");
+
   stack_ensure_sorted (stack);
   g_signal_emit (stack, signals[CHANGED], 0);
 }