Task: Use TBB as Task Scheduler

This patch enables TBB as the default task scheduler. TBB stands for Threading Building Blocks and is developed by Intel. The library contains several threading patters. This patch maps blenders BLI_task_* function to their counterpart. After this patch we can add more patterns. A promising one is TBB:graph that can be used for depsgraph, draw manager and compositor.

Performance changes depends on the actual hardware. It was tested on different hardwares from laptops to workstations and we didn't detected any downgrade of the performance.
* Linux Xeon E5-2699 v4 got FPS boost from 12 to 17 using Spring's 04_010_A.anim.blend.
* AMD Ryzen Threadripper 2990WX 32-Core Animation playback goes from 9.5-10.5 FPS to 13.0-14.0 FPS on Agent 327 , 10_03_B.anim.blend.

Reviewed By: brecht, sergey

Differential Revision: https://developer.blender.org/D7475

1 files changed, 73 insertions, 0 deletions

diff --git a/source/blender/blenlib/intern/task_scheduler.cc b/source/blender/blenlib/intern/task_scheduler.cc
new file mode 100644
index 00000000000..682fee5c46d
--- /dev/null
+++ b/source/blender/blenlib/intern/task_scheduler.cc
@@ -0,0 +1,73 @@
+/*
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ */
+
+/** \file
+ * \ingroup bli
+ *
+ * Task scheduler initialization.
+ */
+
+#include "MEM_guardedalloc.h"
+
+#include "BLI_task.h"
+#include "BLI_threads.h"
+
+#ifdef WITH_TBB
+/* Quiet top level deprecation message, unrelated to API usage here. */
+#  define TBB_SUPPRESS_DEPRECATED_MESSAGES 1
+#  include <tbb/tbb.h>
+#endif
+
+/* Task Scheduler */
+
+static int task_scheduler_num_threads = 1;
+#ifdef WITH_TBB
+static tbb::global_control *task_scheduler_global_control = nullptr;
+#endif
+
+void BLI_task_scheduler_init()
+{
+#ifdef WITH_TBB
+  const int num_threads_override = BLI_system_num_threads_override_get();
+
+  if (num_threads_override > 0) {
+    /* Override number of threads. This settings is used within the lifetime
+     * of tbb::global_control, so we allocate it on the heap. */
+    task_scheduler_global_control = OBJECT_GUARDED_NEW(
+        tbb::global_control, tbb::global_control::max_allowed_parallelism, num_threads_override);
+    task_scheduler_num_threads = num_threads_override;
+  }
+  else {
+    /* Let TBB choose the number of threads. For (legacy) code that calss
+     * BLI_task_scheduler_num_threads() we provide the system thread count.
+     * Ideally such code should be rewritten not to use the number of threads
+     * at all. */
+    task_scheduler_num_threads = BLI_system_thread_count();
+  }
+#endif
+}
+
+void BLI_task_scheduler_exit()
+{
+#ifdef WITH_TBB
+  OBJECT_GUARDED_DELETE(task_scheduler_global_control, tbb::global_control);
+#endif
+}
+
+int BLI_task_scheduler_num_threads()
+{
+  return task_scheduler_num_threads;
+}