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use bevy_utils::HashMap for better performance. TypeId is predefined … (
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#7642)

…u64, so hash safety is not a concern

# Objective

- While reading the code, just noticed the BundleInfo's HashMap is std::collections::HashMap, which uses a slow but safe hasher.

## Solution

- Use bevy_utils::HashMap instead

benchmark diff (I run several times in a linux box, the perf improvement is consistent, though numbers varies from time to time, I paste my last run result here):

``` bash
cargo bench -- spawn
   Compiling bevy_ecs v0.9.0 (/home/lishuo/developer/pr/bevy/crates/bevy_ecs)
   Compiling bevy_app v0.9.0 (/home/lishuo/developer/pr/bevy/crates/bevy_app)
   Compiling benches v0.1.0 (/home/lishuo/developer/pr/bevy/benches)
    Finished bench [optimized] target(s) in 1m 17s
     Running benches/bevy_ecs/change_detection.rs (/home/lishuo/developer/pr/bevy/benches/target/release/deps/change_detection-86c5445d0dc34529)
Gnuplot not found, using plotters backend
     Running benches/bevy_ecs/benches.rs (/home/lishuo/developer/pr/bevy/benches/target/release/deps/ecs-e49b3abe80bfd8c0)
Gnuplot not found, using plotters backend
spawn_commands/2000_entities
                        time:   [153.94 µs 159.19 µs 164.37 µs]
                        change: [-14.706% -11.050% -6.9633%] (p = 0.00 < 0.05)
                        Performance has improved.
spawn_commands/4000_entities
                        time:   [328.77 µs 339.11 µs 349.11 µs]
                        change: [-7.6331% -3.9932% +0.0487%] (p = 0.06 > 0.05)
                        No change in performance detected.
spawn_commands/6000_entities
                        time:   [445.01 µs 461.29 µs 477.36 µs]
                        change: [-16.639% -13.358% -10.006%] (p = 0.00 < 0.05)
                        Performance has improved.
spawn_commands/8000_entities
                        time:   [657.94 µs 677.71 µs 696.95 µs]
                        change: [-8.8708% -5.2591% -1.6847%] (p = 0.01 < 0.05)
                        Performance has improved.

get_or_spawn/individual time:   [452.02 µs 466.70 µs 482.07 µs]
                        change: [-17.218% -14.041% -10.728%] (p = 0.00 < 0.05)
                        Performance has improved.
get_or_spawn/batched    time:   [291.12 µs 301.12 µs 311.31 µs]
                        change: [-12.281% -8.9163% -5.3660%] (p = 0.00 < 0.05)
                        Performance has improved.

spawn_world/1_entities  time:   [81.668 ns 84.284 ns 86.860 ns]
                        change: [-12.251% -6.7872% -1.5402%] (p = 0.02 < 0.05)
                        Performance has improved.
spawn_world/10_entities time:   [789.78 ns 821.96 ns 851.95 ns]
                        change: [-19.738% -14.186% -8.0733%] (p = 0.00 < 0.05)
                        Performance has improved.
spawn_world/100_entities
                        time:   [7.9906 µs 8.2449 µs 8.5013 µs]
                        change: [-12.417% -6.6837% -0.8766%] (p = 0.02 < 0.05)
                        Change within noise threshold.
spawn_world/1000_entities
                        time:   [81.602 µs 84.161 µs 86.833 µs]
                        change: [-13.656% -8.6520% -3.0491%] (p = 0.00 < 0.05)
                        Performance has improved.
Found 1 outliers among 100 measurements (1.00%)
  1 (1.00%) high mild
Benchmarking spawn_world/10000_entities: Warming up for 500.00 ms
Warning: Unable to complete 100 samples in 4.0s. You may wish to increase target time to 4.0s, enable flat sampling, or reduce sample count to 70.
spawn_world/10000_entities
                        time:   [813.02 µs 839.76 µs 865.41 µs]
                        change: [-12.133% -6.1970% -0.2302%] (p = 0.05 < 0.05)
                        Change within noise threshold.
```

---

## Changelog

> This section is optional. If this was a trivial fix, or has no externally-visible impact, you can delete this section.

- use bevy_utils::HashMap for Bundles::bundle_ids

## Migration Guide

> This section is optional. If there are no breaking changes, you can delete this section.

- Not a breaking change, hashmap is internal impl.
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shuoli84 committed Feb 15, 2023
1 parent 0bce784 commit 11a7ff2
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Showing 5 changed files with 13 additions and 7 deletions.
2 changes: 1 addition & 1 deletion crates/bevy_ecs/Cargo.toml
Original file line number Diff line number Diff line change
Expand Up @@ -24,7 +24,7 @@ async-channel = "1.4"
event-listener = "2.5"
thread_local = "1.1.4"
fixedbitset = "0.4.2"
fxhash = "0.2"
rustc-hash = "1.1"
downcast-rs = "1.2"
serde = { version = "1", features = ["derive"] }

Expand Down
3 changes: 1 addition & 2 deletions crates/bevy_ecs/src/archetype.rs
Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,6 @@ use crate::{
storage::{ImmutableSparseSet, SparseArray, SparseSet, SparseSetIndex, TableId, TableRow},
};
use std::{
collections::HashMap,
hash::Hash,
ops::{Index, IndexMut},
};
Expand Down Expand Up @@ -601,7 +600,7 @@ impl SparseSetIndex for ArchetypeComponentId {
pub struct Archetypes {
pub(crate) archetypes: Vec<Archetype>,
pub(crate) archetype_component_count: usize,
archetype_ids: HashMap<ArchetypeIdentity, ArchetypeId>,
archetype_ids: bevy_utils::HashMap<ArchetypeIdentity, ArchetypeId>,
}

impl Archetypes {
Expand Down
5 changes: 3 additions & 2 deletions crates/bevy_ecs/src/bundle.rs
Original file line number Diff line number Diff line change
Expand Up @@ -12,10 +12,11 @@ use crate::{
component::{Component, ComponentId, ComponentStorage, Components, StorageType, Tick},
entity::{Entities, Entity, EntityLocation},
storage::{SparseSetIndex, SparseSets, Storages, Table, TableRow},
TypeIdMap,
};
use bevy_ecs_macros::all_tuples;
use bevy_ptr::OwningPtr;
use std::{any::TypeId, collections::HashMap};
use std::any::TypeId;

/// The `Bundle` trait enables insertion and removal of [`Component`]s from an entity.
///
Expand Down Expand Up @@ -683,7 +684,7 @@ impl<'a, 'b> BundleSpawner<'a, 'b> {
#[derive(Default)]
pub struct Bundles {
bundle_infos: Vec<BundleInfo>,
bundle_ids: HashMap<TypeId, BundleId>,
bundle_ids: TypeIdMap<BundleId>,
}

impl Bundles {
Expand Down
5 changes: 3 additions & 2 deletions crates/bevy_ecs/src/component.rs
Original file line number Diff line number Diff line change
Expand Up @@ -5,6 +5,7 @@ use crate::{
storage::{SparseSetIndex, Storages},
system::{Local, Resource},
world::{FromWorld, World},
TypeIdMap,
};
pub use bevy_ecs_macros::Component;
use bevy_ptr::{OwningPtr, UnsafeCellDeref};
Expand Down Expand Up @@ -400,8 +401,8 @@ impl ComponentDescriptor {
#[derive(Debug, Default)]
pub struct Components {
components: Vec<ComponentInfo>,
indices: std::collections::HashMap<TypeId, usize, fxhash::FxBuildHasher>,
resource_indices: std::collections::HashMap<TypeId, usize, fxhash::FxBuildHasher>,
indices: TypeIdMap<usize>,
resource_indices: TypeIdMap<usize>,
}

impl Components {
Expand Down
5 changes: 5 additions & 0 deletions crates/bevy_ecs/src/lib.rs
Original file line number Diff line number Diff line change
Expand Up @@ -19,6 +19,8 @@ pub mod storage;
pub mod system;
pub mod world;

use std::any::TypeId;

pub use bevy_ptr as ptr;

/// Most commonly used re-exported types.
Expand Down Expand Up @@ -52,6 +54,9 @@ pub mod prelude {

pub use bevy_ecs_macros::all_tuples;

/// A specialized hashmap type with Key of `TypeId`
type TypeIdMap<V> = rustc_hash::FxHashMap<TypeId, V>;

#[cfg(test)]
mod tests {
use crate as bevy_ecs;
Expand Down

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