Struct OpApplyStats 

pub struct OpApplyStats {
    pub applied_count: u64,
    pub reset_count: u64,
    pub app_applied_count: u64,
    pub last_ops: usize,
    pub last_frame_wait: Duration,
    pub last_pre_apply: Duration,
    pub last_translate: Duration,
    pub last_apply_end: Option<Instant>,
}

Live instrumentation of the apply_js_ops hot path. Updated once per frame that applies at least one reconciler op (empty frames leave it untouched), so a benchmark driver — or any consumer — can poll applied_count to detect “my flushed batch has landed” and read the timing of the most recent batch.

Note last_translate measures only the op→command queuing in apply_js_ops; the queued Commands (entity spawn / component insert / hierarchy) execute later at a sync point, and bevy_ui layout later still — neither is included here. last_apply_end is exposed so a downstream timer can bracket those phases (e.g. up to UiSystems::Layout).

Timings are wall-clock, measured on native only; on web they stay zero/None (std::time::Instant is unavailable on wasm).

Fields

applied_count: u64

Count of non-empty op batches applied since startup (one increment per frame that applied at least one op).

reset_count: u64

Count of Op::Resets applied (a cold hot-reload tears the tree down). Devtools uses it to clear its warning-dedup state, so a reloaded app’s re-decoded invalid values flag again (the JS mirror was also reset).

app_applied_count: u64

Like applied_count, but only counting applies that included at least one APP flush (per-batch origin flags — see [FlushFlags]). The devtools panel’s own repaints bump only applied_count; batch-stats emission keys off this so the panel never reports (and re-triggers itself with) its own commits. With no flags channel wired (headless tests), every apply counts as app.

last_ops: usize

Number of ops in the most recently applied batch.

last_frame_wait: Duration

How long the most recently applied ops idled in the channel across the frame boundary: the OLDEST coalesced batch’s [FlushStamps] stamp → this frame’s [FrameStamp]. Structural queue wait, typically ~one vsync period (a Bevy-triggered commit always lands just after that frame’s drain); can exceed one frame when batches coalesce. Zero when the stamp channel or frame stamp is missing (headless tests) and on web.

last_pre_apply: Duration

The in-frame leg of the same span: max(batch stamp, frame start) → the start of apply_js_ops — time eaten by schedules/systems that ran before the drain this frame. With no [FrameStamp] present the whole send→apply span lands here. Zero when no stamp channel is wired (headless tests) and on web.

last_translate: Duration

Time spent translating the most recent batch into ECS commands — the apply_js_ops body only. Excludes command execution and layout.

last_apply_end: Option<Instant>

The instant apply_js_ops finished queuing the most recent batch (native only). A later system can subtract this from a post-layout instant to time command execution + layout.

Trait Implementations

impl Clone for OpApplyStats

fn clone(&self) -> OpApplyStats

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Component for OpApplyStats

where Self: Send + Sync + 'static,

const STORAGE_TYPE: StorageType = ::bevy::ecs::component::StorageType::SparseSet

A constant indicating the storage type used for this component.

type Mutability = Mutable

A marker type to assist Bevy with determining if this component is mutable, or immutable. Mutable components will have Component<Mutability = Mutable>, while immutable components will instead have Component<Mutability = Immutable>.

fn register_required_components( _requiree: ComponentId, required_components: &mut RequiredComponentsRegistrator<'_, '_>, )

Registers required components.

fn clone_behavior() -> ComponentCloneBehavior

Called when registering this component, allowing to override clone function (or disable cloning altogether) for this component.

fn relationship_accessor() -> Option<ComponentRelationshipAccessor<Self>>

Returns ComponentRelationshipAccessor required for working with relationships in dynamic contexts.

fn on_add() -> Option<for<'w> fn(DeferredWorld<'w>, HookContext)>

Gets the on_add ComponentHook for this Component if one is defined.

fn on_insert() -> Option<for<'w> fn(DeferredWorld<'w>, HookContext)>

Gets the on_insert ComponentHook for this Component if one is defined.

fn on_discard() -> Option<for<'w> fn(DeferredWorld<'w>, HookContext)>

Gets the on_discard ComponentHook for this Component if one is defined.

fn on_remove() -> Option<for<'w> fn(DeferredWorld<'w>, HookContext)>

Gets the on_remove ComponentHook for this Component if one is defined.

fn on_despawn() -> Option<for<'w> fn(DeferredWorld<'w>, HookContext)>

Gets the on_despawn ComponentHook for this Component if one is defined.

fn map_entities<E>(_this: &mut Self, _mapper: &mut E)

where E: EntityMapper,

Maps the entities on this component using the given EntityMapper. This is used to remap entities in contexts like scenes and entity cloning. When deriving Component, this is populated by annotating fields containing entities with #[entities]

impl Copy for OpApplyStats

impl Debug for OpApplyStats

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for OpApplyStats

fn default() -> OpApplyStats

Returns the “default value” for a type.

impl Resource for OpApplyStats

where Self: Send + Sync + 'static,