bjoernager/rust
bjoernager/rust
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Auto merge of #124780 - Mark-Simulacrum:lockless-cache, r=lcnr

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Improve VecCache under parallel frontend

This replaces the single Vec allocation with a series of progressively larger buckets. With the cfg for parallel enabled but with -Zthreads=1, this looks like a slight regression in i-count and cycle counts (~1%).

With the parallel frontend at -Zthreads=4, this is an improvement (-5% wall-time from 5.788 to 5.4688 on libcore) than our current Lock-based approach, likely due to reducing the bouncing of the cache line holding the lock. At -Zthreads=32 it's a huge improvement (-46%: 8.829 -> 4.7319 seconds).

try-job: i686-gnu-nopt
try-job: dist-x86_64-linux
This commit is contained in:
bors 2024-11-19 02:07:48 +00:00
commit 5926e82dd1
6 changed files with 458 additions and 65 deletions
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7
compiler/rustc_middle/src/query/keys.rs
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@ -2,6 +2,7 @@
use rustc_hir::def_id::{CrateNum, DefId, LOCAL_CRATE, LocalDefId, LocalModDefId, ModDefId};
use rustc_hir::hir_id::{HirId, OwnerId};
use rustc_query_system::dep_graph::DepNodeIndex;
use rustc_query_system::query::{DefIdCache, DefaultCache, SingleCache, VecCache};
use rustc_span::symbol::{Ident, Symbol};
use rustc_span::{DUMMY_SP, Span};
@ -111,7 +112,7 @@ impl<'tcx> Key for mir::interpret::LitToConstInput<'tcx> {
}
impl Key for CrateNum {
type Cache<V> = VecCache<Self, V>;
type Cache<V> = VecCache<Self, V, DepNodeIndex>;
fn default_span(&self, _: TyCtxt<'_>) -> Span {
DUMMY_SP
@ -128,7 +129,7 @@ impl AsLocalKey for CrateNum {
}
impl Key for OwnerId {
type Cache<V> = VecCache<Self, V>;
type Cache<V> = VecCache<Self, V, DepNodeIndex>;
fn default_span(&self, tcx: TyCtxt<'_>) -> Span {
self.to_def_id().default_span(tcx)
@ -140,7 +141,7 @@ impl Key for OwnerId {
}
impl Key for LocalDefId {
type Cache<V> = VecCache<Self, V>;
type Cache<V> = VecCache<Self, V, DepNodeIndex>;
fn default_span(&self, tcx: TyCtxt<'_>) -> Span {
self.to_def_id().default_span(tcx)