# Objective
Fixes#12966
## Solution
Renaming multi_threaded feature to match snake case
## Migration Guide
Bevy feature multi-threaded should be refered to multi_threaded from now
on.
# Objective
- bevy usually use `Parallel::scope` to collect items from `par_iter`,
but `scope` will be called with every satifified items. it will cause a
lot of unnecessary lookup.
## Solution
- similar to Rayon ,we introduce `for_each_init` for `par_iter` which
only be invoked when spawn a task for a group of items.
---
## Changelog
- added `for_each_init`
## Performance
`check_visibility ` in `many_foxes `
~40% performance gain in `check_visibility`.
---------
Co-authored-by: James Liu <contact@jamessliu.com>
# Objective
Allow parallel iteration over events, resolve#10766
## Solution
- Add `EventParIter` which works similarly to `QueryParIter`,
implementing a `for_each{_with_id}` operator.
I chose to not mirror `EventIteratorWithId` and instead implement both
operations on a single struct.
- Reuse `BatchingStrategy` from `QueryParIter`
## Changelog
- `EventReader` now supports parallel event iteration using
`par_read().for_each(|event| ...)`.
---------
Co-authored-by: James Liu <contact@jamessliu.com>
Co-authored-by: Pablo Reinhardt <126117294+pablo-lua@users.noreply.github.com>
# Objective
- I daily drive nightly Rust when developing Bevy, so I notice when new
warnings are raised by `cargo check` and Clippy.
- `cargo +nightly clippy` raises a few of these new warnings.
## Solution
- Fix most warnings from `cargo +nightly clippy`
- I skipped the docs-related warnings because some were covered by
#12692.
- Use `Clone::clone_from` in applicable scenarios, which can sometimes
avoid an extra allocation.
- Implement `Default` for structs that have a `pub const fn new() ->
Self` method.
- Fix an occurrence where generic constraints were defined in both `<C:
Trait>` and `where C: Trait`.
- Removed generic constraints that were implied by the `Bundle` trait.
---
## Changelog
- `BatchingStrategy`, `NonGenericTypeCell`, and `GenericTypeCell` now
implement `Default`.
# Objective
Other than the exposed functions for reading matched tables and
archetypes, a `QueryState` does not actually need both internal Vecs for
storing matched archetypes and tables. In practice, it will only use one
of the two depending on if it uses dense or archetypal iteration.
Same vein as #12474. The goal is to reduce the memory overhead of using
queries, which Bevy itself, ecosystem plugins, and end users are already
fairly liberally using.
## Solution
Add `StorageId`, which is a union over `TableId` and `ArchetypeId`, and
store only one of the two at runtime. Read the slice as if it was one ID
depending on whether the query is dense or not.
This follows in the same vein as #5085; however, this one directly
impacts heap memory usage at runtime, while #5085 primarily targeted
transient pointers that might not actually exist at runtime.
---
## Changelog
Changed: `QueryState::matched_tables` now returns an iterator instead of
a reference to a slice.
Changed: `QueryState::matched_archetypes` now returns an iterator
instead of a reference to a slice.
## Migration Guide
`QueryState::matched_tables` and `QueryState::matched_archetypes` does
not return a reference to a slice, but an iterator instead. You may need
to use iterator combinators or collect them into a Vec to use it as a
slice.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
- Add the new `-Zcheck-cfg` checks to catch more warnings
- Fixes#12091
## Solution
- Create a new `cfg-check` to the CI that runs `cargo check -Zcheck-cfg
--workspace` using cargo nightly (and fails if there are warnings)
- Fix all warnings generated by the new check
---
## Changelog
- Remove all redundant imports
- Fix cfg wasm32 targets
- Add 3 dead code exceptions (should StandardColor be unused?)
- Convert ios_simulator to a feature (I'm not sure if this is the right
way to do it, but the check complained before)
## Migration Guide
No breaking changes
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
Since #10776 split `WorldQuery` to `WorldQueryData` and
`WorldQueryFilter`, it should be clear that the query is actually
composed of two parts. It is not factually correct to call "query" only
the data part. Therefore I suggest to rename the `Q` parameter to `D` in
`Query` and related items.
As far as I know, there shouldn't be breaking changes from renaming
generic type parameters.
## Solution
I used a combination of rust-analyzer go to reference and `Ctrl-F`ing
various patterns to catch as many cases as possible. Hopefully I got
them all. Feel free to check if you're concerned of me having missed
some.
## Notes
This and #10779 have many lines in common, so merging one will cause a
lot of merge conflicts to the other.
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
After #6547, `Query::for_each` has been capable of automatic
vectorization on certain queries, which is seeing a notable (>50% CPU
time improvements) for iteration. However, `Query::for_each` isn't
idiomatic Rust, and lacks the flexibility of iterator combinators.
Ideally, `Query::iter` and friends should be able to achieve the same
results. However, this does seem to blocked upstream
(rust-lang/rust#104914) by Rust's loop optimizations.
## Solution
This is an intermediate solution and refactor. This moves the
`Query::for_each` implementation onto the `Iterator::fold`
implementation for `QueryIter` instead. This should result in the same
automatic vectorization optimization on all `Iterator` functions that
internally use fold, including `Iterator::for_each`, `Iterator::count`,
etc.
With this, it should close the gap between the two completely.
Internally, this PR changes `Query::for_each` to use
`query.iter().for_each(..)` instead of the duplicated implementation.
Separately, the duplicate implementations of internal iteration (i.e.
`Query::par_for_each`) now use portions of the current `Query::for_each`
implementation factored out into their own functions.
This also massively cleans up our internal fragmentation of internal
iteration options, deduplicating the iteration code used in `for_each`
and `par_iter().for_each()`.
---
## Changelog
Changed: `Query::for_each`, `Query::for_each_mut`, `Query::for_each`,
and `Query::for_each_mut` have been moved to `QueryIter`'s
`Iterator::for_each` implementation, and still retains their performance
improvements over normal iteration. These APIs are deprecated in 0.13
and will be removed in 0.14.
---------
Co-authored-by: JoJoJet <21144246+JoJoJet@users.noreply.github.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
- Fixes#7680
- This is an updated for https://github.com/bevyengine/bevy/pull/8899
which had the same objective but fell a long way behind the latest
changes
## Solution
The traits `WorldQueryData : WorldQuery` and `WorldQueryFilter :
WorldQuery` have been added and some of the types and functions from
`WorldQuery` has been moved into them.
`ReadOnlyWorldQuery` has been replaced with `ReadOnlyWorldQueryData`.
`WorldQueryFilter` is safe (as long as `WorldQuery` is implemented
safely).
`WorldQueryData` is unsafe - safely implementing it requires that
`Self::ReadOnly` is a readonly version of `Self` (this used to be a
safety requirement of `WorldQuery`)
The type parameters `Q` and `F` of `Query` must now implement
`WorldQueryData` and `WorldQueryFilter` respectively.
This makes it impossible to accidentally use a filter in the data
position or vice versa which was something that could lead to bugs.
~~Compile failure tests have been added to check this.~~
It was previously sometimes useful to use `Option<With<T>>` in the data
position. Use `Has<T>` instead in these cases.
The `WorldQuery` derive macro has been split into separate derive macros
for `WorldQueryData` and `WorldQueryFilter`.
Previously it was possible to derive both `WorldQuery` for a struct that
had a mixture of data and filter items. This would not work correctly in
some cases but could be a useful pattern in others. *This is no longer
possible.*
---
## Notes
- The changes outside of `bevy_ecs` are all changing type parameters to
the new types, updating the macro use, or replacing `Option<With<T>>`
with `Has<T>`.
- All `WorldQueryData` types always returned `true` for `IS_ARCHETYPAL`
so I moved it to `WorldQueryFilter` and
replaced all calls to it with `true`. That should be the only logic
change outside of the macro generation code.
- `Changed<T>` and `Added<T>` were being generated by a macro that I
have expanded. Happy to revert that if desired.
- The two derive macros share some functions for implementing
`WorldQuery` but the tidiest way I could find to implement them was to
give them a ton of arguments and ask clippy to ignore that.
## Changelog
### Changed
- Split `WorldQuery` into `WorldQueryData` and `WorldQueryFilter` which
now have separate derive macros. It is not possible to derive both for
the same type.
- `Query` now requires that the first type argument implements
`WorldQueryData` and the second implements `WorldQueryFilter`
## Migration Guide
- Update derives
```rust
// old
#[derive(WorldQuery)]
#[world_query(mutable, derive(Debug))]
struct CustomQuery {
entity: Entity,
a: &'static mut ComponentA
}
#[derive(WorldQuery)]
struct QueryFilter {
_c: With<ComponentC>
}
// new
#[derive(WorldQueryData)]
#[world_query_data(mutable, derive(Debug))]
struct CustomQuery {
entity: Entity,
a: &'static mut ComponentA,
}
#[derive(WorldQueryFilter)]
struct QueryFilter {
_c: With<ComponentC>
}
```
- Replace `Option<With<T>>` with `Has<T>`
```rust
/// old
fn my_system(query: Query<(Entity, Option<With<ComponentA>>)>)
{
for (entity, has_a_option) in query.iter(){
let has_a:bool = has_a_option.is_some();
//todo!()
}
}
/// new
fn my_system(query: Query<(Entity, Has<ComponentA>)>)
{
for (entity, has_a) in query.iter(){
//todo!()
}
}
```
- Fix queries which had filters in the data position or vice versa.
```rust
// old
fn my_system(query: Query<(Entity, With<ComponentA>)>)
{
for (entity, _) in query.iter(){
//todo!()
}
}
// new
fn my_system(query: Query<Entity, With<ComponentA>>)
{
for entity in query.iter(){
//todo!()
}
}
// old
fn my_system(query: Query<AnyOf<(&ComponentA, With<ComponentB>)>>)
{
for (entity, _) in query.iter(){
//todo!()
}
}
// new
fn my_system(query: Query<Option<&ComponentA>, Or<(With<ComponentA>, With<ComponentB>)>>)
{
for entity in query.iter(){
//todo!()
}
}
```
---------
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
# Objective
The default division for a `usize` rounds down which means the batch
sizes were too small when the `max_size` isn't exactly divisible by the
batch count.
## Solution
Changing the division to round up fixes this which can dramatically
improve performance when using `par_iter`.
I created a small example to proof this out and measured some results. I
don't know if it's worth committing this permanently so I left it out of
the PR for now.
```rust
use std::{thread, time::Duration};
use bevy::{
prelude::*,
window::{PresentMode, WindowPlugin},
};
fn main() {
App::new()
.add_plugins((DefaultPlugins.set(WindowPlugin {
primary_window: Some(Window {
present_mode: PresentMode::AutoNoVsync,
..default()
}),
..default()
}),))
.add_systems(Startup, spawn)
.add_systems(Update, update_counts)
.run();
}
#[derive(Component, Default, Debug, Clone, Reflect)]
pub struct Count(u32);
fn spawn(mut commands: Commands) {
// Worst case
let tasks = bevy::tasks::available_parallelism() * 5 - 1;
// Best case
// let tasks = bevy::tasks::available_parallelism() * 5 + 1;
for _ in 0..tasks {
commands.spawn(Count(0));
}
}
// changing the bounds of the text will cause a recomputation
fn update_counts(mut count_query: Query<&mut Count>) {
count_query.par_iter_mut().for_each(|mut count| {
count.0 += 1;
thread::sleep(Duration::from_millis(10))
});
}
```
## Results
I ran this four times, with and without the change, with best case
(should favour the old maths) and worst case (should favour the new
maths) task numbers.
### Worst case
Before the change the batches were 9 on each thread, plus the 5
remainder ran on one of the threads in addition. With the change its 10
on each thread apart from one which has 9. The results show a decrease
from ~140ms to ~100ms which matches what you would expect from the maths
(`10 * 10ms` vs `(9 + 4) * 10ms`).
### Best case
Before the change the batches were 10 on each thread, plus the 1
remainder ran on one of the threads in addition. With the change its 11
on each thread apart from one which has 5. The results slightly favour
the new change but are basically identical as the total time is
determined by the worse case which is `11 * 10ms` for both tests.
# Objective
The `QueryParIter::for_each_mut` function is required when doing
parallel iteration with mutable queries.
This results in an unfortunate stutter:
`query.par_iter_mut().par_for_each_mut()` ('mut' is repeated).
## Solution
- Make `for_each` compatible with mutable queries, and deprecate
`for_each_mut`. In order to prevent `for_each` from being called
multiple times in parallel, we take ownership of the QueryParIter.
---
## Changelog
- `QueryParIter::for_each` is now compatible with mutable queries.
`for_each_mut` has been deprecated as it is now redundant.
## Migration Guide
The method `QueryParIter::for_each_mut` has been deprecated and is no
longer functional. Use `for_each` instead, which now supports mutable
queries.
```rust
// Before:
query.par_iter_mut().for_each_mut(|x| ...);
// After:
query.par_iter_mut().for_each(|x| ...);
```
The method `QueryParIter::for_each` now takes ownership of the
`QueryParIter`, rather than taking a shared reference.
```rust
// Before:
let par_iter = my_query.par_iter().batching_strategy(my_batching_strategy);
par_iter.for_each(|x| {
// ...Do stuff with x...
par_iter.for_each(|y| {
// ...Do nested stuff with y...
});
});
// After:
my_query.par_iter().batching_strategy(my_batching_strategy).for_each(|x| {
// ...Do stuff with x...
my_query.par_iter().batching_strategy(my_batching_strategy).for_each(|y| {
// ...Do nested stuff with y...
});
});
```
# Objective
Fixes#6689.
## Solution
Add `single-threaded` as an optional non-default feature to `bevy_ecs`
and `bevy_tasks` that:
- disable the `ParallelExecutor` as a default runner
- disables the multi-threaded `TaskPool`
- internally replace `QueryParIter::for_each` calls with
`Query::for_each`.
Removed the `Mutex` and `Arc` usage in the single-threaded task pool.
## Future Work/TODO
Create type aliases for `Mutex`, `Arc` that change to single-threaaded
equivalents where possible.
---
## Changelog
Added: Optional default feature `multi-theaded` to that enables
multithreaded parallelism in the engine. Disabling it disables all
multithreading in exchange for higher single threaded performance. Does
nothing on WASM targets.
---------
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
# Objective
- The function `QueryParIter::for_each_unchecked` is a footgun: the only
ways to use it soundly can be done in safe code using `for_each` or
`for_each_mut`. See [this discussion on
discord](https://discord.com/channels/691052431525675048/749335865876021248/1118642977275924583).
## Solution
- Make `for_each_unchecked` private.
---
## Changelog
- Removed `QueryParIter::for_each_unchecked`. All use-cases of this
method were either unsound or doable in safe code using `for_each` or
`for_each_mut`.
## Migration Guide
The method `QueryParIter::for_each_unchecked` has been removed -- use
`for_each` or `for_each_mut` instead. If your use case can not be
achieved using either of these, then your code was likely unsound.
If you have a use-case for `for_each_unchecked` that you believe is
sound, please [open an
issue](https://github.com/bevyengine/bevy/issues/new/choose).
# Objective
Follow-up to #6404 and #8292.
Mutating the world through a shared reference is surprising, and it
makes the meaning of `&World` unclear: sometimes it gives read-only
access to the entire world, and sometimes it gives interior mutable
access to only part of it.
This is an up-to-date version of #6972.
## Solution
Use `UnsafeWorldCell` for all interior mutability. Now, `&World`
*always* gives you read-only access to the entire world.
---
## Changelog
TODO - do we still care about changelogs?
## Migration Guide
Mutating any world data using `&World` is now considered unsound -- the
type `UnsafeWorldCell` must be used to achieve interior mutability. The
following methods now accept `UnsafeWorldCell` instead of `&World`:
- `QueryState`: `get_unchecked`, `iter_unchecked`,
`iter_combinations_unchecked`, `for_each_unchecked`,
`get_single_unchecked`, `get_single_unchecked_manual`.
- `SystemState`: `get_unchecked_manual`
```rust
let mut world = World::new();
let mut query = world.query::<&mut T>();
// Before:
let t1 = query.get_unchecked(&world, entity_1);
let t2 = query.get_unchecked(&world, entity_2);
// After:
let world_cell = world.as_unsafe_world_cell();
let t1 = query.get_unchecked(world_cell, entity_1);
let t2 = query.get_unchecked(world_cell, entity_2);
```
The methods `QueryState::validate_world` and
`SystemState::matches_world` now take a `WorldId` instead of `&World`:
```rust
// Before:
query_state.validate_world(&world);
// After:
query_state.validate_world(world.id());
```
The methods `QueryState::update_archetypes` and
`SystemState::update_archetypes` now take `UnsafeWorldCell` instead of
`&World`:
```rust
// Before:
query_state.update_archetypes(&world);
// After:
query_state.update_archetypes(world.as_unsafe_world_cell_readonly());
```
# Objective
Title.
---------
Co-authored-by: François <mockersf@gmail.com>
Co-authored-by: Alice Cecile <alice.i.cecile@gmail.com>
Co-authored-by: James Liu <contact@jamessliu.com>
# Objective
Fixes#3184. Fixes#6640. Fixes#4798. Using `Query::par_for_each(_mut)` currently requires a `batch_size` parameter, which affects how it chunks up large archetypes and tables into smaller chunks to run in parallel. Tuning this value is difficult, as the performance characteristics entirely depends on the state of the `World` it's being run on. Typically, users will just use a flat constant and just tune it by hand until it performs well in some benchmarks. However, this is both error prone and risks overfitting the tuning on that benchmark.
This PR proposes a naive automatic batch-size computation based on the current state of the `World`.
## Background
`Query::par_for_each(_mut)` schedules a new Task for every archetype or table that it matches. Archetypes/tables larger than the batch size are chunked into smaller tasks. Assuming every entity matched by the query has an identical workload, this makes the worst case scenario involve using a batch size equal to the size of the largest matched archetype or table. Conversely, a batch size of `max {archetype, table} size / thread count * COUNT_PER_THREAD` is likely the sweetspot where the overhead of scheduling tasks is minimized, at least not without grouping small archetypes/tables together.
There is also likely a strict minimum batch size below which the overhead of scheduling these tasks is heavier than running the entire thing single-threaded.
## Solution
- [x] Remove the `batch_size` from `Query(State)::par_for_each` and friends.
- [x] Add a check to compute `batch_size = max {archeytpe/table} size / thread count * COUNT_PER_THREAD`
- [x] ~~Panic if thread count is 0.~~ Defer to `for_each` if the thread count is 1 or less.
- [x] Early return if there is no matched table/archetype.
- [x] Add override option for users have queries that strongly violate the initial assumption that all iterated entities have an equal workload.
---
## Changelog
Changed: `Query::par_for_each(_mut)` has been changed to `Query::par_iter(_mut)` and will now automatically try to produce a batch size for callers based on the current `World` state.
## Migration Guide
The `batch_size` parameter for `Query(State)::par_for_each(_mut)` has been removed. These calls will automatically compute a batch size for you. Remove these parameters from all calls to these functions.
Before:
```rust
fn parallel_system(query: Query<&MyComponent>) {
query.par_for_each(32, |comp| {
...
});
}
```
After:
```rust
fn parallel_system(query: Query<&MyComponent>) {
query.par_iter().for_each(|comp| {
...
});
}
```
Co-authored-by: Arnav Choubey <56453634+x-52@users.noreply.github.com>
Co-authored-by: Robert Swain <robert.swain@gmail.com>
Co-authored-by: François <mockersf@gmail.com>
Co-authored-by: Corey Farwell <coreyf@rwell.org>
Co-authored-by: Aevyrie <aevyrie@gmail.com>
