[Bf-blender-cvs] SVN commit: /data/svn/bf-blender [59134] branches/soc-2013-depsgraph_mt/ source: Recent spinlock commit made scheduling unsafe for threading

[Sergey Sharybin]

Revision: 59134
          http://projects.blender.org/scm/viewvc.php?view=rev&root=bf-blender&revision=59134
Author:   nazgul
Date:     2013-08-14 09:24:15 +0000 (Wed, 14 Aug 2013)
Log Message:
-----------
Recent spinlock commit made scheduling unsafe for threading

Namely, it caused nodes be adding to the pool multiple times.

Returned spin back, but use it only in cases node valency is
zero. So now valency is decreasing without any locks, then
if it's zero spin lock happens, node color (which indicates
whether node is scheduled or not) happens. Actual new task
creation happens outside of locks.

This might sound a bit complicated, but it's straightforward
code which is free from any thread synchronization latency.

Modified Paths:
--------------
    branches/soc-2013-depsgraph_mt/source/blender/blenkernel/BKE_depsgraph.h
    branches/soc-2013-depsgraph_mt/source/blender/blenkernel/intern/blender.c
    branches/soc-2013-depsgraph_mt/source/blender/blenkernel/intern/depsgraph.c
    branches/soc-2013-depsgraph_mt/source/blender/windowmanager/intern/wm_playanim.c
    branches/soc-2013-depsgraph_mt/source/creator/creator.c
    branches/soc-2013-depsgraph_mt/source/gameengine/GamePlayer/ghost/GPG_ghost.cpp

Modified: branches/soc-2013-depsgraph_mt/source/blender/blenkernel/BKE_depsgraph.h
===================================================================
--- branches/soc-2013-depsgraph_mt/source/blender/blenkernel/BKE_depsgraph.h	2013-08-14 09:14:33 UTC (rev 59133)
+++ branches/soc-2013-depsgraph_mt/source/blender/blenkernel/BKE_depsgraph.h	2013-08-14 09:24:15 UTC (rev 59134)
@@ -118,6 +118,10 @@
 
 /* ** Threaded update ** */
 
+/* Global initialization/deinitialization */
+void DAG_threaded_init(void);
+void DAG_threaded_exit(void);
+
 /* Initialize the DAG for threaded update. */
 void DAG_threaded_update_begin(struct Scene *scene);
 

Modified: branches/soc-2013-depsgraph_mt/source/blender/blenkernel/intern/blender.c
===================================================================
--- branches/soc-2013-depsgraph_mt/source/blender/blenkernel/intern/blender.c	2013-08-14 09:14:33 UTC (rev 59133)
+++ branches/soc-2013-depsgraph_mt/source/blender/blenkernel/intern/blender.c	2013-08-14 09:24:15 UTC (rev 59134)
@@ -120,6 +120,7 @@
 	
 	IMB_exit();
 	BKE_images_exit();
+	DAG_threaded_exit();
 
 	BKE_brush_system_exit();
 

Modified: branches/soc-2013-depsgraph_mt/source/blender/blenkernel/intern/depsgraph.c
===================================================================
--- branches/soc-2013-depsgraph_mt/source/blender/blenkernel/intern/depsgraph.c	2013-08-14 09:14:33 UTC (rev 59133)
+++ branches/soc-2013-depsgraph_mt/source/blender/blenkernel/intern/depsgraph.c	2013-08-14 09:24:15 UTC (rev 59134)
@@ -42,6 +42,7 @@
 #include "BLI_utildefines.h"
 #include "BLI_listbase.h"
 #include "BLI_ghash.h"
+#include "BLI_threads.h"
 
 #include "DNA_anim_types.h"
 #include "DNA_camera_types.h"
@@ -2658,6 +2659,18 @@
 
 /* ************************  DAG FOR THREADED UPDATE  ********************* */
 
+static SpinLock threaded_update_lock;
+
+void DAG_threaded_init(void)
+{
+	BLI_spin_init(&threaded_update_lock);
+}
+
+void DAG_threaded_exit(void)
+{
+	BLI_spin_end(&threaded_update_lock);
+}
+
 /* Initialize the DAG for threaded update.
  *
  * Sets up all the data needed for faster check whether DAG node is
@@ -2670,6 +2683,7 @@
 	/* We reset valency to zero first... */
 	for (node = scene->theDag->DagNode.first; node; node = node->next) {
 		node->valency = 0;
+		node->color = DAG_WHITE;
 	}
 
 	/* ... and then iterate over all the nodes and
@@ -2698,7 +2712,16 @@
 
 	for (node = scene->theDag->DagNode.first; node; node = node->next) {
 		if (node->valency == 0) {
-			func(node, user_data);
+			bool need_schedule;
+
+			BLI_spin_lock(&threaded_update_lock);
+			need_schedule = node->color == DAG_WHITE;
+			node->color = DAG_BLACK;
+			BLI_spin_unlock(&threaded_update_lock);
+
+			if (need_schedule) {
+				func(node, user_data);
+			}
 		}
 	}
 }
@@ -2738,11 +2761,21 @@
 	DagAdjList *itA;
 
 	for (itA = node->child; itA; itA = itA->next) {
-		if (itA->node != node) {
-			atomic_sub_uint32(&itA->node->valency, 1);
+		DagNode *child_node = itA->node;
+		if (child_node != node) {
+			atomic_sub_uint32(&child_node->valency, 1);
 
-			if (itA->node->valency == 0) {
-				func(itA->node, user_data);
+			if (child_node->valency == 0) {
+				bool need_schedule;
+
+				BLI_spin_lock(&threaded_update_lock);
+				need_schedule = child_node->color == DAG_WHITE;
+				child_node->color = DAG_BLACK;
+				BLI_spin_unlock(&threaded_update_lock);
+
+				if (need_schedule) {
+					func(child_node, user_data);
+				}
 			}
 		}
 	}

Modified: branches/soc-2013-depsgraph_mt/source/blender/windowmanager/intern/wm_playanim.c
===================================================================
--- branches/soc-2013-depsgraph_mt/source/blender/windowmanager/intern/wm_playanim.c	2013-08-14 09:14:33 UTC (rev 59133)
+++ branches/soc-2013-depsgraph_mt/source/blender/windowmanager/intern/wm_playanim.c	2013-08-14 09:24:15 UTC (rev 59134)
@@ -60,6 +60,7 @@
 #include "IMB_imbuf.h"
 
 #include "BKE_blender.h"
+#include "BKE_depsgraph.h"
 #include "BKE_global.h"
 #include "BKE_image.h"
 
@@ -1198,6 +1199,7 @@
 	
 	IMB_exit();
 	BKE_images_exit();
+	DAG_threaded_exit();
 
 	totblock = MEM_get_memory_blocks_in_use();
 	if (totblock != 0) {

Modified: branches/soc-2013-depsgraph_mt/source/creator/creator.c
===================================================================
--- branches/soc-2013-depsgraph_mt/source/creator/creator.c	2013-08-14 09:14:33 UTC (rev 59133)
+++ branches/soc-2013-depsgraph_mt/source/creator/creator.c	2013-08-14 09:24:15 UTC (rev 59134)
@@ -1519,6 +1519,7 @@
 	IMB_init();
 	BKE_images_init();
 	BKE_modifier_init();
+	DAG_threaded_init();
 
 	BKE_brush_system_init();
 

Modified: branches/soc-2013-depsgraph_mt/source/gameengine/GamePlayer/ghost/GPG_ghost.cpp
===================================================================
--- branches/soc-2013-depsgraph_mt/source/gameengine/GamePlayer/ghost/GPG_ghost.cpp	2013-08-14 09:14:33 UTC (rev 59133)
+++ branches/soc-2013-depsgraph_mt/source/gameengine/GamePlayer/ghost/GPG_ghost.cpp	2013-08-14 09:24:15 UTC (rev 59134)
@@ -458,6 +458,7 @@
 	IMB_init();
 	BKE_images_init();
 	BKE_modifier_init();
+	DAG_threaded_init();
 
 #ifdef WITH_FFMPEG
 	IMB_ffmpeg_init();
@@ -1081,6 +1082,7 @@
 
 	IMB_exit();
 	BKE_images_exit();
+	DAG_threaded_exit();
 
 	SYS_DeleteSystem(syshandle);