Cycles: threading optimizations

* Multithreaded image loading, each thread can load a separate image.
* Better multithreading for multiple instanced meshes, different threads can now
  build BVH's for different meshes, rather than all cooperating on the same mesh.
  Especially noticeable for dynamic BVH building for the viewport, gave about
  2x faster build on 8 core in fairly complex scene with many objects.
* The main thread waiting for worker threads can now also work itself, so
  (num_cores + 1) threads will be working, this supposedly gives better
  performance on some operating systems, but did not measure performance for
  this very detailed yet.

1 files changed, 31 insertions, 23 deletions

diff --git a/intern/cycles/render/image.cpp b/intern/cycles/render/image.cpp
index 78b8f06c7b4..3e6052338c0 100644
--- a/intern/cycles/render/image.cpp
+++ b/intern/cycles/render/image.cpp
@@ -324,8 +324,10 @@ bool ImageManager::file_load_float_image(Image *img, device_vector<float4>& tex_
 	return true;
 }
 
-void ImageManager::device_load_image(Device *device, DeviceScene *dscene, int slot)
+void ImageManager::device_load_image(Device *device, DeviceScene *dscene, int slot, Progress *progress)
 {
+	if(progress->get_cancel())
+		return;
 	if(osl_texture_system)
 		return;
 
@@ -342,6 +344,9 @@ void ImageManager::device_load_image(Device *device, DeviceScene *dscene, int sl
 	}
 
 	if(is_float) {
+		string filename = path_filename(float_images[slot]->filename);
+		progress->set_status("Updating Images", "Loading " + filename);
+
 		device_vector<float4>& tex_img = dscene->tex_float_image[slot - TEX_IMAGE_FLOAT_START];
 
 		if(tex_img.device_pointer)
@@ -365,6 +370,9 @@ void ImageManager::device_load_image(Device *device, DeviceScene *dscene, int sl
 		device->tex_alloc(name.c_str(), tex_img, true, true);
 	}
 	else {
+		string filename = path_filename(images[slot]->filename);
+		progress->set_status("Updating Images", "Loading " + filename);
+
 		device_vector<uchar4>& tex_img = dscene->tex_image[slot];
 
 		if(tex_img.device_pointer)
@@ -387,6 +395,8 @@ void ImageManager::device_load_image(Device *device, DeviceScene *dscene, int sl
 
 		device->tex_alloc(name.c_str(), tex_img, true, true);
 	}
+
+	img->need_load = false;
 }
 
 void ImageManager::device_free_image(Device *device, DeviceScene *dscene, int slot)
@@ -431,39 +441,37 @@ void ImageManager::device_update(Device *device, DeviceScene *dscene, Progress&
 {
 	if(!need_update)
 		return;
+	
+	TaskPool pool;
 
 	for(size_t slot = 0; slot < images.size(); slot++) {
-		if(images[slot]) {
-			if(images[slot]->users == 0) {
-				device_free_image(device, dscene, slot);
-			}
-			else if(images[slot]->need_load) {
-				string name = path_filename(images[slot]->filename);
-				progress.set_status("Updating Images", "Loading " + name);
-				device_load_image(device, dscene, slot);
-				images[slot]->need_load = false;
-			}
+		if(!images[slot])
+			continue;
 
-			if(progress.get_cancel()) return;
+		if(images[slot]->users == 0) {
+			device_free_image(device, dscene, slot);
+		}
+		else if(images[slot]->need_load) {
+			if(!osl_texture_system) 
+				pool.push(function_bind(&ImageManager::device_load_image, this, device, dscene, slot, &progress));
 		}
 	}
 
 	for(size_t slot = 0; slot < float_images.size(); slot++) {
-		if(float_images[slot]) {
-			if(float_images[slot]->users == 0) {
-				device_free_image(device, dscene, slot + TEX_IMAGE_FLOAT_START);
-			}
-			else if(float_images[slot]->need_load) {
-				string name = path_filename(float_images[slot]->filename);
-				progress.set_status("Updating Images", "Loading " + name);
-				device_load_image(device, dscene, slot + TEX_IMAGE_FLOAT_START);
-				float_images[slot]->need_load = false;
-			}
+		if(!float_images[slot])
+			continue;
 
-			if(progress.get_cancel()) return;
+		if(float_images[slot]->users == 0) {
+			device_free_image(device, dscene, slot + TEX_IMAGE_FLOAT_START);
+		}
+		else if(float_images[slot]->need_load) {
+			if(!osl_texture_system) 
+				pool.push(function_bind(&ImageManager::device_load_image, this, device, dscene, slot + TEX_IMAGE_FLOAT_START, &progress));
 		}
 	}
 
+	pool.wait_work();
+
 	need_update = false;
 }