mirror of
https://github.com/bevyengine/bevy
synced 2024-11-25 14:10:19 +00:00
9bda913e36
# Objective - fix #12853 - Make `Table::allocate` faster ## Solution The PR consists of multiple steps: 1) For the component data: create a new data-structure that's similar to `BlobVec` but doesn't store `len` & `capacity` inside of it: "BlobArray" (name suggestions welcome) 2) For the `Tick` data: create a new data-structure that's similar to `ThinSlicePtr` but supports dynamic reallocation: "ThinArrayPtr" (name suggestions welcome) 3) Create a new data-structure that's very similar to `Column` that doesn't store `len` & `capacity` inside of it: "ThinColumn" 4) Adjust the `Table` implementation to use `ThinColumn` instead of `Column` The result is that only one set of `len` & `capacity` is stored in `Table`, in `Table::entities` ### Notes Regarding Performance Apart from shaving off some excess memory in `Table`, the changes have also brought noteworthy performance improvements: The previous implementation relied on `Vec::reserve` & `BlobVec::reserve`, but that redundantly repeated the same if statement (`capacity` == `len`). Now that check could be made at the `Table` level because the capacity and length of all the columns are synchronized; saving N branches per allocation. The result is a respectable performance improvement per every `Table::reserve` (and subsequently `Table::allocate`) call. I'm hesitant to give exact numbers because I don't have a lot of experience in profiling and benchmarking, but these are the results I got so far: *`add_remove_big/table` benchmark after the implementation:*  *`add_remove_big/table` benchmark in main branch (measured in comparison to the implementation):*  *`add_remove_very_big/table` benchmark after the implementation:*  *`add_remove_very_big/table` benchmark in main branch (measured in comparison to the implementation):*  cc @james7132 to verify --- ## Changelog - New data-structure that's similar to `BlobVec` but doesn't store `len` & `capacity` inside of it: `BlobArray` - New data-structure that's similar to `ThinSlicePtr` but supports dynamic allocation:`ThinArrayPtr` - New data-structure that's very similar to `Column` that doesn't store `len` & `capacity` inside of it: `ThinColumn` - Adjust the `Table` implementation to use `ThinColumn` instead of `Column` - New benchmark: `add_remove_very_big` to benchmark the performance of spawning a lot of entities with a lot of components (15) each ## Migration Guide `Table` now uses `ThinColumn` instead of `Column`. That means that methods that previously returned `Column`, will now return `ThinColumn` instead. `ThinColumn` has a much more limited and low-level API, but you can still achieve the same things in `ThinColumn` as you did in `Column`. For example, instead of calling `Column::get_added_tick`, you'd call `ThinColumn::get_added_ticks_slice` and index it to get the specific added tick. --------- Co-authored-by: James Liu <contact@jamessliu.com>
26 lines
451 B
Text
26 lines
451 B
Text
/target
|
|
crates/*/target
|
|
**/*.rs.bk
|
|
Cargo.lock
|
|
.cargo/config
|
|
.cargo/config.toml
|
|
/.idea
|
|
/.vscode
|
|
.zed
|
|
/benches/target
|
|
/tools/compile_fail_utils/target
|
|
dxcompiler.dll
|
|
dxil.dll
|
|
|
|
# Generated by "examples/scene/scene.rs"
|
|
assets/scenes/load_scene_example-new.scn.ron
|
|
|
|
# Generated by "examples/window/screenshot.rs"
|
|
**/screenshot-*.png
|
|
|
|
assets/**/*.meta
|
|
crates/bevy_asset/imported_assets
|
|
imported_assets
|
|
|
|
example_showcase_config.ron
|
|
example-showcase-reports/
|