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Make ECS benchmark more representative (#2941)

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# Objective

- The addition was being optimised out in the `for_each` loop, but not the `for` loop
- Previously this meant that the `for_each` loop looked 3 times as fast - it's actually only 2 times as fast
- Effectively, the addition take one unit of time, the for_each takes one unit of time, and the for loop version takes two units of time. 

## Solution

- `black_box` the count in each loop

Note that this does not fix `for_each` being faster than `for`, unfortunately.
This commit is contained in:
Daniel McNab 2022-02-03 22:34:29 +00:00
parent c44f8b2b68
commit 6ac9d6876f
1 changed files with 5 additions and 1 deletions
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6
benches/benches/bevy_ecs/world_get.rs
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@ -23,7 +23,7 @@ const RANGE: std::ops::Range<u32> = 5..6;
fn setup<T: Component + Default>(entity_count: u32) -> World {
let mut world = World::default();
world.spawn_batch((0..entity_count).map(|_| (T::default(),)));
world
black_box(world)
}
fn world_entity(criterion: &mut Criterion) {
@ -126,6 +126,7 @@ fn world_query_iter(criterion: &mut Criterion) {
for comp in query.iter(&world) {
black_box(comp);
count += 1;
black_box(count);
}
assert_eq!(black_box(count), entity_count);
});
@ -139,6 +140,7 @@ fn world_query_iter(criterion: &mut Criterion) {
for comp in query.iter(&world) {
black_box(comp);
count += 1;
black_box(count);
}
assert_eq!(black_box(count), entity_count);
});
@ -163,6 +165,7 @@ fn world_query_for_each(criterion: &mut Criterion) {
query.for_each(&world, |comp| {
black_box(comp);
count += 1;
black_box(count);
});
assert_eq!(black_box(count), entity_count);
});
@ -176,6 +179,7 @@ fn world_query_for_each(criterion: &mut Criterion) {
query.for_each(&world, |comp| {
black_box(comp);
count += 1;
black_box(count);
});
assert_eq!(black_box(count), entity_count);
});