Differential D12367 Diff 41308 intern/cycles/integrator/work_tile_scheduler.h

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intern/cycles/integrator/work_tile_scheduler.h

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				/*
				* Copyright 2011-2021 Blender Foundation
				*
				* Licensed under the Apache License, Version 2.0 (the "License");
				* you may not use this file except in compliance with the License.
				* You may obtain a copy of the License at
				*
				* http://www.apache.org/licenses/LICENSE-2.0
				*
				* Unless required by applicable law or agreed to in writing, software
				* distributed under the License is distributed on an "AS IS" BASIS,
				* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
				* See the License for the specific language governing permissions and
				* limitations under the License.
				*/

				#pragma once

				#include "integrator/tile.h"
				#include "util/util_types.h"

				CCL_NAMESPACE_BEGIN

				class BufferParams;

				struct KernelWorkTile;

				/* Scheduler of device work tiles.
				* Takes care of feeding multiple devices running in parallel a work which needs to be done. */
				class WorkTileScheduler {
				public:
				WorkTileScheduler();

				/* MAximum path states which are allowed to be used by a single scheduled work tile.
				*
				* Affects the scheduled work size: the work size will be as big as possible, but will not exceed
				* this number of states. */
				void set_max_num_path_states(int max_num_path_states);

				/* Scheduling will happen for pixels within a big tile denotes by its parameters. */
				void reset(const BufferParams &buffer_params, int sample_start, int samples_num);

				/* Get work for a device.
				* Returns true if there is still work to be done and initialize the work tile to all
				* parameters of this work. If there is nothing remaining to be done, returns false and the
				* work tile is kept unchanged.
				*
				* Optionally pass max_work_size to do nothing if there is no tile small enough. */
				bool get_work(KernelWorkTile *work_tile, const int max_work_size = 0);

				protected:
				void reset_scheduler_state();

				/* Maximum allowed path states to be used.
				*
				* TODO(sergey): Naming can be improved. The fact that this is a limiting factor based on the
				* number of path states is kind of a detail. Is there a more generic term from the scheduler
				* point of view? */
				int max_num_path_states_ = 0;

				/* Offset in pixels within a global buffer. */
				int2 image_full_offset_px_ = make_int2(0, 0);

				/* dimensions of the currently rendering image in pixels. */
				int2 image_size_px_ = make_int2(0, 0);

				/* Offset and stride of the buffer within which scheduing is happenning.
				* Will be passed over to the KernelWorkTile. */
				int offset_, stride_;

				/* Start sample of index and number of samples which are to be rendered.
				* The scheduler will cover samples range of [start, start + num] over the entire image
				* (splitting into a smaller work tiles). */
				int sample_start_ = 0;
				int samples_num_ = 0;

				/* Tile size which be scheduled for rendering. */
				TileSize tile_size_;

				/* Number of tiles in X and Y axis of the image. */
				int num_tiles_x_, num_tiles_y_;

				/* Total number of tiles on the image.
				* Pre-calculated as `num_tiles_x_ * num_tiles_y_` and re-used in the `get_work()`.
				*
				* TODO(sergey): Is this an over-optimization? Maybe it's unmeasurable to calculate the value
				* in the `get_work()`? */
				int total_tiles_num_ = 0;

				/* In the case when the number of sam[les in the `tile_size_` is lower than samples_num_ denotes
				* how many tiles are to be "stacked" to cover the entire requested range of samples. */
				int num_tiles_per_sample_range_ = 0;

				int next_work_index_ = 0;
				int total_work_size_ = 0;
				};

				CCL_NAMESPACE_END