Tweak to early threaded update escape

Issue was caused by some objects being in bMain and tagged
for update but not being in the DAG. This means objects
wouldn't be updated and their recalc flag remains untouched
triggering threaded for the next frame.

Solved by tweaking POST_UPDATE_HANDLER_WORKAROUND in the way
that it checks objects' recalc flags from the DAG, not from
the bMain. This will work a bit longer since DAG stored more
nodes than objects in the scene, but this code only runs in
cases when there're some objects tagged for update, which
keeps overall CPU usage on such a workaround pretty low.

Now CPU usage on 11a_comp scene from project Pampa went down
from ~15% down to ~5% (2,69 release uses ~%7).

Pointed by Thomas Dinges in IRC.

3 files changed, 19 insertions, 13 deletions

diff --git a/source/blender/blenkernel/BKE_depsgraph.h b/source/blender/blenkernel/BKE_depsgraph.h
index df7e9561c46..bfd01545f86 100644
--- a/source/blender/blenkernel/BKE_depsgraph.h
+++ b/source/blender/blenkernel/BKE_depsgraph.h
@@ -128,7 +128,7 @@ int  DAG_id_type_tagged(struct Main *bmain, short idtype);
 void DAG_scene_flush_update(struct Main *bmain, struct Scene *sce, unsigned int lay, const short do_time);
 void DAG_ids_flush_tagged(struct Main *bmain);
 void DAG_ids_check_recalc(struct Main *bmain, struct Scene *scene, int time);
-void DAG_ids_clear_recalc(struct Main *bmain);
+void DAG_ids_clear_recalc(struct Main *bmain, struct Scene *scene);
 
 /* Armature: sorts the bones according to dependencies between them */
 
diff --git a/source/blender/blenkernel/intern/depsgraph.c b/source/blender/blenkernel/intern/depsgraph.c
index 1c36cccf1e6..b9c9572d599 100644
--- a/source/blender/blenkernel/intern/depsgraph.c
+++ b/source/blender/blenkernel/intern/depsgraph.c
@@ -2471,7 +2471,7 @@ void DAG_ids_check_recalc(Main *bmain, Scene *scene, int time)
 
 #define POST_UPDATE_HANDLER_WORKAROUND
 
-void DAG_ids_clear_recalc(Main *bmain)
+void DAG_ids_clear_recalc(Main *bmain, Scene *scene)
 {
 	ListBase *lbarray[MAX_LIBARRAY];
 	bNodeTree *ntree;
@@ -2479,6 +2479,21 @@ void DAG_ids_clear_recalc(Main *bmain)
 
 #ifdef POST_UPDATE_HANDLER_WORKAROUND
 	bool have_updated_objects = false;
+
+	if (DAG_id_type_tagged(bmain, ID_OB)) {
+		DagNode *node;
+		for (node = scene->theDag->DagNode.first; node; node = node->next) {
+			if (node->type == ID_OB) {
+				Object *object = (Object *) node->ob;
+				if (object->recalc & OB_RECALC_ALL) {
+					have_updated_objects = true;
+					break;
+				}
+			}
+		}
+	}
+#else
+	(void) scene;  /* Unused. */
 #endif
 
 	/* loop over all ID types */
@@ -2495,15 +2510,6 @@ void DAG_ids_clear_recalc(Main *bmain)
 				if (id->flag & (LIB_ID_RECALC | LIB_ID_RECALC_DATA))
 					id->flag &= ~(LIB_ID_RECALC | LIB_ID_RECALC_DATA);
 
-#ifdef POST_UPDATE_HANDLER_WORKAROUND
-				if (GS(id->name) == ID_OB) {
-					Object *object = (Object *) id;
-					if (object->recalc & OB_RECALC_ALL) {
-						have_updated_objects = true;
-					}
-				}
-#endif
-
 				/* some ID's contain semi-datablock nodetree */
 				ntree = ntreeFromID(id);
 				if (ntree && (ntree->id.flag & (LIB_ID_RECALC | LIB_ID_RECALC_DATA)))
diff --git a/source/blender/blenkernel/intern/scene.c b/source/blender/blenkernel/intern/scene.c
index c6a2dfb4482..8b3866076be 100644
--- a/source/blender/blenkernel/intern/scene.c
+++ b/source/blender/blenkernel/intern/scene.c
@@ -1563,7 +1563,7 @@ void BKE_scene_update_tagged(EvaluationContext *eval_ctx, Main *bmain, Scene *sc
 	DAG_ids_check_recalc(bmain, scene, FALSE);
 
 	/* clear recalc flags */
-	DAG_ids_clear_recalc(bmain);
+	DAG_ids_clear_recalc(bmain, scene);
 }
 
 /* applies changes right away, does all sets too */
@@ -1639,7 +1639,7 @@ void BKE_scene_update_for_newframe(EvaluationContext *eval_ctx, Main *bmain, Sce
 	DAG_ids_check_recalc(bmain, sce, TRUE);
 
 	/* clear recalc flags */
-	DAG_ids_clear_recalc(bmain);
+	DAG_ids_clear_recalc(bmain, sce);
 
 #ifdef DETAILED_ANALYSIS_OUTPUT
 	fprintf(stderr, "frame update start_time %f duration %f\n", start_time, PIL_check_seconds_timer() - start_time);