Struct heron::rapier_plugin::rapier::crossbeam::utils::CachePadded [−]
#[repr(align(128))]pub struct CachePadded<T> { /* fields omitted */ }
Pads and aligns a value to the length of a cache line.
In concurrent programming, sometimes it is desirable to make sure commonly accessed pieces of
data are not placed into the same cache line. Updating an atomic value invalidates the whole
cache line it belongs to, which makes the next access to the same cache line slower for other
CPU cores. Use CachePadded
to ensure updating one piece of data doesn’t invalidate other
cached data.
Size and alignment
Cache lines are assumed to be N bytes long, depending on the architecture:
- On x86-64, aarch64, and powerpc64, N = 128.
- On arm, mips, mips64, and riscv64, N = 32.
- On s390x, N = 256.
- On all others, N = 64.
Note that N is just a reasonable guess and is not guaranteed to match the actual cache line length of the machine the program is running on. On modern Intel architectures, spatial prefetcher is pulling pairs of 64-byte cache lines at a time, so we pessimistically assume that cache lines are 128 bytes long.
The size of CachePadded<T>
is the smallest multiple of N bytes large enough to accommodate
a value of type T
.
The alignment of CachePadded<T>
is the maximum of N bytes and the alignment of T
.
Examples
Alignment and padding:
use crossbeam_utils::CachePadded; let array = [CachePadded::new(1i8), CachePadded::new(2i8)]; let addr1 = &*array[0] as *const i8 as usize; let addr2 = &*array[1] as *const i8 as usize; assert!(addr2 - addr1 >= 64); assert_eq!(addr1 % 64, 0); assert_eq!(addr2 % 64, 0);
When building a concurrent queue with a head and a tail index, it is wise to place them in different cache lines so that concurrent threads pushing and popping elements don’t invalidate each other’s cache lines:
use crossbeam_utils::CachePadded; use std::sync::atomic::AtomicUsize; struct Queue<T> { head: CachePadded<AtomicUsize>, tail: CachePadded<AtomicUsize>, buffer: *mut T, }
Implementations
impl<T> CachePadded<T>
pub const fn new(t: T) -> CachePadded<T>
Pads and aligns a value to the length of a cache line.
Examples
use crossbeam_utils::CachePadded; let padded_value = CachePadded::new(1);
pub fn into_inner(self) -> T
Returns the inner value.
Examples
use crossbeam_utils::CachePadded; let padded_value = CachePadded::new(7); let value = padded_value.into_inner(); assert_eq!(value, 7);
Trait Implementations
impl<T> Clone for CachePadded<T> where
T: Clone,
T: Clone,
pub fn clone(&self) -> CachePadded<T>
pub fn clone_from(&mut self, source: &Self)
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impl<T> Copy for CachePadded<T> where
T: Copy,
T: Copy,
impl<T> Debug for CachePadded<T> where
T: Debug,
T: Debug,
impl<T> Default for CachePadded<T> where
T: Default,
T: Default,
pub fn default() -> CachePadded<T>
impl<T> Deref for CachePadded<T>
impl<T> DerefMut for CachePadded<T>
impl<T> Eq for CachePadded<T> where
T: Eq,
T: Eq,
impl<T> From<T> for CachePadded<T>
pub fn from(t: T) -> CachePadded<T>
impl<T> Hash for CachePadded<T> where
T: Hash,
T: Hash,
pub fn hash<__H>(&self, state: &mut __H) where
__H: Hasher,
__H: Hasher,
pub fn hash_slice<H>(data: &[Self], state: &mut H) where
H: Hasher,
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H: Hasher,
impl<T> PartialEq<CachePadded<T>> for CachePadded<T> where
T: PartialEq<T>,
T: PartialEq<T>,
pub fn eq(&self, other: &CachePadded<T>) -> bool
pub fn ne(&self, other: &CachePadded<T>) -> bool
impl<T> Send for CachePadded<T> where
T: Send,
T: Send,
impl<T> StructuralEq for CachePadded<T>
impl<T> StructuralPartialEq for CachePadded<T>
impl<T> Sync for CachePadded<T> where
T: Sync,
T: Sync,
Auto Trait Implementations
impl<T> RefUnwindSafe for CachePadded<T> where
T: RefUnwindSafe,
T: RefUnwindSafe,
impl<T> Unpin for CachePadded<T> where
T: Unpin,
T: Unpin,
impl<T> UnwindSafe for CachePadded<T> where
T: UnwindSafe,
T: UnwindSafe,
Blanket Implementations
impl<T> Any for T where
T: 'static + ?Sized,
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T: 'static + ?Sized,
impl<T> Any for T where
T: Any,
T: Any,
impl<T> Borrow<T> for T where
T: ?Sized,
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T: ?Sized,
impl<T> BorrowMut<T> for T where
T: ?Sized,
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T: ?Sized,
pub fn borrow_mut(&mut self) -> &mut T
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impl<T> CallHasher for T where
T: Hash + ?Sized,
T: Hash + ?Sized,
pub default fn get_hash<H, B>(value: &H, build_hasher: &B) -> u64 where
B: BuildHasher,
H: Hash + ?Sized,
B: BuildHasher,
H: Hash + ?Sized,
impl<T> CallHasher for T where
T: Hash,
T: Hash,
impl<T> CloneAny for T where
T: Any + Clone,
T: Any + Clone,
impl<T> Component for T where
T: 'static + Send + Sync,
T: 'static + Send + Sync,
impl<T> Downcast for T where
T: Any,
T: Any,
pub fn into_any(self: Box<T, Global>) -> Box<dyn Any + 'static, Global>
pub fn into_any_rc(self: Rc<T>) -> Rc<dyn Any + 'static>
pub fn as_any(&self) -> &(dyn Any + 'static)
pub fn as_any_mut(&mut self) -> &mut (dyn Any + 'static)
impl<T> Downcast<T> for T
impl<T> DowncastSync for T where
T: Any + Send + Sync,
T: Any + Send + Sync,
impl<T> DynEq for T where
T: Any + Eq,
T: Any + Eq,
pub fn as_any(&self) -> &(dyn Any + 'static)
pub fn dyn_eq(&self, other: &(dyn DynEq + 'static)) -> bool
impl<T> DynHash for T where
T: DynEq + Hash,
T: DynEq + Hash,
impl<Q, K> Equivalent<K> for Q where
K: Borrow<Q> + ?Sized,
Q: Eq + ?Sized,
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K: Borrow<Q> + ?Sized,
Q: Eq + ?Sized,
pub fn equivalent(&self, key: &K) -> bool
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impl<T> From<!> for T
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impl<T> From<T> for T
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impl<T> FromWorld for T where
T: Default,
T: Default,
pub fn from_world(_world: &mut World) -> T
impl<T> Instrument for T
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pub fn instrument(self, span: Span) -> Instrumented<Self>
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pub fn in_current_span(self) -> Instrumented<Self>
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impl<T, U> Into<U> for T where
U: From<T>,
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U: From<T>,
impl<T> Pointable for T
pub const ALIGN: usize
type Init = T
The type for initializers.
pub unsafe fn init(init: <T as Pointable>::Init) -> usize
pub unsafe fn deref<'a>(ptr: usize) -> &'a T
pub unsafe fn deref_mut<'a>(ptr: usize) -> &'a mut T
pub unsafe fn drop(ptr: usize)
impl<T> Same<T> for T
type Output = T
Should always be Self
impl<T> Scalar for T where
T: Copy + PartialEq<T> + Debug + Any,
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T: Copy + PartialEq<T> + Debug + Any,
impl<SS, SP> SupersetOf<SS> for SP where
SS: SubsetOf<SP>,
SS: SubsetOf<SP>,
pub fn to_subset(&self) -> Option<SS>
pub fn is_in_subset(&self) -> bool
pub fn to_subset_unchecked(&self) -> SS
pub fn from_subset(element: &SS) -> SP
impl<T> ToOwned for T where
T: Clone,
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T: Clone,
type Owned = T
The resulting type after obtaining ownership.
pub fn to_owned(&self) -> T
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pub fn clone_into(&self, target: &mut T)
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impl<T, U> TryFrom<U> for T where
U: Into<T>,
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U: Into<T>,
type Error = Infallible
The type returned in the event of a conversion error.
pub fn try_from(value: U) -> Result<T, <T as TryFrom<U>>::Error>
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impl<T, U> TryInto<U> for T where
U: TryFrom<T>,
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U: TryFrom<T>,
type Error = <U as TryFrom<T>>::Error
The type returned in the event of a conversion error.
pub fn try_into(self) -> Result<U, <U as TryFrom<T>>::Error>
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impl<T> TypeData for T where
T: 'static + Send + Sync + Clone,
T: 'static + Send + Sync + Clone,
pub fn clone_type_data(&self) -> Box<dyn TypeData + 'static, Global>
impl<T> Upcast<T> for T
impl<V, T> VZip<V> for T where
V: MultiLane<T>,
V: MultiLane<T>,