bjoernager/rust
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Optimize lock_shards

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This commit is contained in:
John Kåre Alsaker 2023-08-17 11:07:50 +02:00
parent b74cb78d63
commit f458b112f8
4 changed files with 42 additions and 34 deletions
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25
compiler/rustc_data_structures/src/sharded.rs
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@ -2,9 +2,12 @@ use crate::fx::{FxHashMap, FxHasher};
#[cfg(parallel_compiler)]
use crate::sync::{is_dyn_thread_safe, CacheAligned};
use crate::sync::{Lock, LockGuard};
#[cfg(parallel_compiler)]
use itertools::Either;
use std::borrow::Borrow;
use std::collections::hash_map::RawEntryMut;
use std::hash::{Hash, Hasher};
use std::iter;
use std::mem;
// 32 shards is sufficient to reduce contention on an 8-core Ryzen 7 1700,
@ -70,19 +73,27 @@ impl<T> Sharded<T> {
}
}
pub fn lock_shards(&self) -> Vec<LockGuard<'_, T>> {
#[inline]
pub fn lock_shards(&self) -> impl Iterator<Item = LockGuard<'_, T>> {
match self {
Self::Single(single) => vec![single.lock()],
#[cfg(not(parallel_compiler))]
Self::Single(single) => iter::once(single.lock()),
#[cfg(parallel_compiler)]
Self::Shards(shards) => shards.iter().map(|shard| shard.0.lock()).collect(),
Self::Single(single) => Either::Left(iter::once(single.lock())),
#[cfg(parallel_compiler)]
Self::Shards(shards) => Either::Right(shards.iter().map(|shard| shard.0.lock())),
}
}
pub fn try_lock_shards(&self) -> Option<Vec<LockGuard<'_, T>>> {
#[inline]
pub fn try_lock_shards(&self) -> impl Iterator<Item = Option<LockGuard<'_, T>>> {
match self {
Self::Single(single) => Some(vec![single.try_lock()?]),
#[cfg(not(parallel_compiler))]
Self::Single(single) => iter::once(single.try_lock()),
#[cfg(parallel_compiler)]
Self::Shards(shards) => shards.iter().map(|shard| shard.0.try_lock()).collect(),
Self::Single(single) => Either::Left(iter::once(single.try_lock())),
#[cfg(parallel_compiler)]
Self::Shards(shards) => Either::Right(shards.iter().map(|shard| shard.0.try_lock())),
}
}
}
@ -101,7 +112,7 @@ pub type ShardedHashMap<K, V> = Sharded<FxHashMap<K, V>>;
impl<K: Eq, V> ShardedHashMap<K, V> {
pub fn len(&self) -> usize {
self.lock_shards().iter().map(|shard| shard.len()).sum()
self.lock_shards().map(|shard| shard.len()).sum()
}
}