d1df97bd48
I observed allocation becoming a bottleneck when building the depsgraph with scenes with many simple data-blocks. One of the main culprits was the struct that encodes relations between nodes in the graph. Instead of allocating each `Relation` with a separate allocation call, combine them into a `LinearAllocator`. That is must faster because it allocates in large chunks and just bumps an offset on each allocation. In a test file with 30 thousand cube objects, I observe a 1.18x improvement in depsgraph evaluation time, from 1370 to 1163 ms. The depsgraph isn't completely re-allocated when it's rebuilt, so the allocator added in this PR has to be cleared manually. In the future, it can be used for other structs or potentially strings. Pull Request: https://projects.blender.org/blender/blender/pulls/137303
97 lines
2.8 KiB
C++
97 lines
2.8 KiB
C++
/* SPDX-FileCopyrightText: 2015 Blender Authors
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*
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* SPDX-License-Identifier: GPL-2.0-or-later */
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/** \file
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* \ingroup depsgraph
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*/
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#include "DEG_depsgraph_debug.hh"
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#include "intern/builder/deg_builder_transitive.h"
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#include "intern/node/deg_node.hh"
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#include "intern/node/deg_node_component.hh"
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#include "intern/node/deg_node_operation.hh"
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#include "intern/debug/deg_debug.h"
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#include "intern/depsgraph.hh"
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#include "intern/depsgraph_relation.hh"
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namespace blender::deg {
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/* -------------------------------------------------- */
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/* Performs a transitive reduction to remove redundant relations.
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* https://en.wikipedia.org/wiki/Transitive_reduction
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*
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* XXX The current implementation is somewhat naive and has O(V*E) worst case
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* runtime.
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* A more optimized algorithm can be implemented later, e.g.
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*
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* http://www.sciencedirect.com/science/article/pii/0304397588900321/pdf?md5=3391e309b708b6f9cdedcd08f84f4afc&pid=1-s2.0-0304397588900321-main.pdf
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*
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* Care has to be taken to make sure the algorithm can handle the cyclic case
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* too! (unless we can to prevent this case early on).
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*/
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enum {
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OP_VISITED = 1,
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OP_REACHABLE = 2,
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};
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static void deg_graph_tag_paths_recursive(Node *node)
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{
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if (node->custom_flags & OP_VISITED) {
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return;
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}
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node->custom_flags |= OP_VISITED;
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for (Relation *rel : node->inlinks) {
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deg_graph_tag_paths_recursive(rel->from);
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/* Do this only in inlinks loop, so the target node does not get
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* flagged. */
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rel->from->custom_flags |= OP_REACHABLE;
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}
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}
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void deg_graph_transitive_reduction(Depsgraph *graph)
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{
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int num_removed_relations = 0;
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Vector<Relation *> relations_to_remove;
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for (OperationNode *target : graph->operations) {
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/* Clear tags. */
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for (OperationNode *node : graph->operations) {
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node->custom_flags = 0;
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}
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/* Mark nodes from which we can reach the target
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* start with children, so the target node and direct children are not
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* flagged. */
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target->custom_flags |= OP_VISITED;
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for (Relation *rel : target->inlinks) {
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deg_graph_tag_paths_recursive(rel->from);
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}
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/* Remove redundant paths to the target. */
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for (Relation *rel : target->inlinks) {
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if (rel->from->type == NodeType::TIMESOURCE) {
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/* HACK: time source nodes don't get "custom_flags" flag
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* set/cleared. */
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/* TODO: there will be other types in future, so iterators above
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* need modifying. */
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continue;
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}
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if (rel->from->custom_flags & OP_REACHABLE) {
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relations_to_remove.append(rel);
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}
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}
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for (Relation *rel : relations_to_remove) {
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rel->unlink();
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}
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num_removed_relations += relations_to_remove.size();
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relations_to_remove.clear();
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}
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DEG_DEBUG_PRINTF((::Depsgraph *)graph, BUILD, "Removed %d relations\n", num_removed_relations);
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}
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} // namespace blender::deg
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