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Speedup resource lookup in Res and ResMut #23174

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caa2353
speedup resource lookup
Trashtalk217 Feb 28, 2026
fed5730
fix
Trashtalk217 Feb 28, 2026
5aac54f
clippy
Trashtalk217 Feb 28, 2026
2d53f3d
Merge branch 'main' into speedup-resource-lookup
Trashtalk217 Feb 28, 2026
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2 changes: 1 addition & 1 deletion crates/bevy_ecs/src/resource.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -114,7 +114,7 @@ impl DerefMut for ResourceEntities {
#[cfg_attr(feature = "bevy_reflect", derive(Reflect), reflect(Component, Debug))]
#[derive(Component, Debug)]
#[component(on_insert, on_discard, on_despawn)]
pub struct IsResource(ComponentId);
pub struct IsResource(pub ComponentId);

impl IsResource {
/// Creates a new instance with the given `component_id`
Expand Down
48 changes: 30 additions & 18 deletions crates/bevy_ecs/src/system/system_param.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -9,12 +9,12 @@ use crate::{
bundle::Bundles,
change_detection::{ComponentTicksMut, ComponentTicksRef, Tick},
component::{ComponentId, Components},
entity::{Entities, EntityAllocator},
entity::{Entities, Entity, EntityAllocator},
query::{
Access, FilteredAccess, FilteredAccessSet, IterQueryData, QueryData, QueryFilter,
QuerySingleError, QueryState, ReadOnlyQueryData,
},
resource::{Resource, IS_RESOURCE},
resource::{IsResource, Resource, IS_RESOURCE},
storage::NonSendData,
system::{Query, Single, SystemMeta},
world::{
Expand Down Expand Up @@ -738,15 +738,20 @@ unsafe impl<'a, T: Resource> ReadOnlySystemParam for Res<'a, T> {}
// SAFETY: Res ComponentId access is applied to SystemMeta. If this Res
// conflicts with any prior access, a panic will occur.
unsafe impl<'a, T: Resource> SystemParam for Res<'a, T> {
type State = ComponentId;
type State = (ComponentId, Entity);
type Item<'w, 's> = Res<'w, T>;

fn init_state(world: &mut World) -> Self::State {
world.components_registrator().register_component::<T>()
let component_id = world.components_registrator().register_component::<T>();
if let Some(entity) = world.resource_entities().get(component_id) {
return (component_id, *entity);
}
let entity = world.spawn(IsResource(component_id)).id();
(component_id, entity)
}

fn init_access(
&component_id: &Self::State,
&(component_id, _): &Self::State,
system_meta: &mut SystemMeta,
component_access_set: &mut FilteredAccessSet,
_world: &mut World,
Expand Down Expand Up @@ -777,13 +782,12 @@ unsafe impl<'a, T: Resource> SystemParam for Res<'a, T> {

#[inline]
unsafe fn validate_param(
&mut component_id: &mut Self::State,
&mut (component_id, entity): &mut Self::State,
_system_meta: &SystemMeta,
world: UnsafeWorldCell,
) -> Result<(), SystemParamValidationError> {
// SAFETY: Read-only access to the resource
if let Some(entity) = unsafe { world.resource_entities() }.get(component_id)
&& let Ok(entity_ref) = world.get_entity(*entity)
if let Ok(entity_ref) = world.get_entity(entity)
&& entity_ref.contains_id(component_id)
{
Ok(())
Expand All @@ -796,13 +800,15 @@ unsafe impl<'a, T: Resource> SystemParam for Res<'a, T> {

#[inline]
unsafe fn get_param<'w, 's>(
&mut component_id: &'s mut Self::State,
&mut (component_id, entity): &'s mut Self::State,
system_meta: &SystemMeta,
world: UnsafeWorldCell<'w>,
change_tick: Tick,
) -> Self::Item<'w, 's> {
let (ptr, ticks) = world
.get_resource_with_ticks(component_id)
.get_entity(entity)
.ok()
.and_then(|entity| entity.get_with_ticks(component_id))
.unwrap_or_else(|| {
panic!(
"Resource requested by {} does not exist: {}",
Expand All @@ -826,15 +832,20 @@ unsafe impl<'a, T: Resource> SystemParam for Res<'a, T> {
// SAFETY: Res ComponentId access is applied to SystemMeta. If this Res
// conflicts with any prior access, a panic will occur.
unsafe impl<'a, T: Resource> SystemParam for ResMut<'a, T> {
type State = ComponentId;
type State = (ComponentId, Entity);
type Item<'w, 's> = ResMut<'w, T>;

fn init_state(world: &mut World) -> Self::State {
world.components_registrator().register_component::<T>()
let component_id = world.components_registrator().register_component::<T>();
if let Some(entity) = world.resource_entities().get(component_id) {
return (component_id, *entity);
}
let entity = world.spawn(IsResource(component_id)).id();
(component_id, entity)
}

fn init_access(
&component_id: &Self::State,
&(component_id, _): &Self::State,
system_meta: &mut SystemMeta,
component_access_set: &mut FilteredAccessSet,
_world: &mut World,
Expand Down Expand Up @@ -868,13 +879,12 @@ unsafe impl<'a, T: Resource> SystemParam for ResMut<'a, T> {

#[inline]
unsafe fn validate_param(
&mut component_id: &mut Self::State,
&mut (component_id, entity): &mut Self::State,
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@cart cart Feb 28, 2026 •
edited
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The redundant work in validate_param, which is done immediately before get_param never felt great to me. This isn't a problem exclusive to Res/ResMut, but it is certainly present.

I think doing validation as part of get_param is more defensible from a performance perspective.

I think it is worth doing some benchmarks where we skip validation (as-in, across all SystemParams), just to see what price we're paying here.

_system_meta: &SystemMeta,
world: UnsafeWorldCell,
) -> Result<(), SystemParamValidationError> {
// SAFETY: Read-only access to the resource.
if let Some(entity) = unsafe { world.resource_entities() }.get(component_id)
&& let Ok(entity_ref) = world.get_entity(*entity)
if let Ok(entity_ref) = world.get_entity(entity)
&& entity_ref.contains_id(component_id)
{
Ok(())
Expand All @@ -887,13 +897,15 @@ unsafe impl<'a, T: Resource> SystemParam for ResMut<'a, T> {

#[inline]
unsafe fn get_param<'w, 's>(
&mut component_id: &'s mut Self::State,
&mut (component_id, entity): &'s mut Self::State,
system_meta: &SystemMeta,
world: UnsafeWorldCell<'w>,
change_tick: Tick,
) -> Self::Item<'w, 's> {
let value = world
.get_resource_mut_by_id(component_id)
.get_entity(entity)
.ok()
.and_then(|entity| entity.get_mut_by_id(component_id).ok())
.unwrap_or_else(|| {
panic!(
"Resource requested by {} does not exist: {}",
Expand Down
33 changes: 33 additions & 0 deletions crates/bevy_ecs/src/world/unsafe_world_cell.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1121,6 +1121,39 @@ impl<'w> UnsafeEntityCell<'w> {
}
}

/// Gets the component of the given [`ComponentId`] from the entity with the tick information.
///
/// **You should prefer to use the typed API where possible and only
/// use this in cases where the actual component types are not known at
/// compile time.**
///
/// Unlike [`UnsafeEntityCell::get`], this returns a raw pointer to the component,
/// which is only valid while the `'w` borrow of the lifetime is active.
///
/// # Safety
/// It is the caller's responsibility to ensure that
/// - the [`UnsafeEntityCell`] has permission to access the component
/// - no other mutable references to the component exist at the same time
#[inline]
pub unsafe fn get_with_ticks(
self,
component_id: ComponentId,
) -> Option<(Ptr<'w>, ComponentTickCells<'w>)> {
let info = self.world.components().get_info(component_id)?;
// SAFETY:
// - caller ensures there is no `&mut World`
// - caller ensures there are no mutable borrows of this resource
// - caller ensures that we have permission to access this resource
// - storage_type and location are valid
get_component_and_ticks(
self.world,
component_id,
info.storage_type(),
self.entity,
self.location,
)
}

/// Retrieves a mutable untyped reference to the given `entity`'s [`Component`] of the given [`ComponentId`].
/// Returns `None` if the `entity` does not have a [`Component`] of the given type.
///
Expand Down
2 changes: 1 addition & 1 deletion crates/bevy_render/src/extract_param.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -101,7 +101,7 @@ where
world: UnsafeWorldCell,
) -> Result<(), SystemParamValidationError> {
// SAFETY: Read-only access to world data registered in `init_state`.
let result = unsafe { world.get_resource_by_id(state.main_world_state) };
let result = unsafe { world.get_resource_by_id(state.main_world_state.0) };
let Some(main_world) = result else {
return Err(SystemParamValidationError::invalid::<Self>(
"`MainWorld` resource does not exist",
Expand Down