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Auto merge of #111713 - Zoxc:lock-switch, r=nnethercote

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Use conditional synchronization for Lock

This changes `Lock` to use synchronization only if `mode::is_dyn_thread_safe` could be true. This reduces overhead for the parallel compiler running with 1 thread.

The emitters are changed to use `DynSend` instead of `Send` so they can still use `Lock`.

A Rayon thread pool is not used with 1 thread anymore, as session globals contains `Lock`s which are no longer `Sync`.

Performance improvement with 1 thread and `cfg(parallel_compiler)`:
<table><tr><td rowspan="2">Benchmark</td><td colspan="1"><b>Before</b></th><td colspan="2"><b>After</b></th></tr><tr><td align="right">Time</td><td align="right">Time</td><td align="right">%</th></tr><tr><td>🟣 <b>clap</b>:check</td><td align="right">1.7665s</td><td align="right">1.7336s</td><td align="right">💚  -1.86%</td></tr><tr><td>🟣 <b>hyper</b>:check</td><td align="right">0.2780s</td><td align="right">0.2736s</td><td align="right">💚  -1.61%</td></tr><tr><td>🟣 <b>regex</b>:check</td><td align="right">0.9994s</td><td align="right">0.9824s</td><td align="right">💚  -1.70%</td></tr><tr><td>🟣 <b>syn</b>:check</td><td align="right">1.5875s</td><td align="right">1.5656s</td><td align="right">💚  -1.38%</td></tr><tr><td>🟣 <b>syntex_syntax</b>:check</td><td align="right">6.0682s</td><td align="right">5.9532s</td><td align="right">💚  -1.90%</td></tr><tr><td>Total</td><td align="right">10.6997s</td><td align="right">10.5083s</td><td align="right">💚  -1.79%</td></tr><tr><td>Summary</td><td align="right">1.0000s</td><td align="right">0.9831s</td><td align="right">💚  -1.69%</td></tr></table>

cc `@SparrowLii`
This commit is contained in:
bors 2023-08-30 08:03:43 +00:00
commit 61efe9d298
13 changed files with 368 additions and 139 deletions
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36
compiler/rustc_interface/src/util.rs
View file

@ -137,10 +137,8 @@ fn get_stack_size() -> Option<usize> {
env::var_os("RUST_MIN_STACK").is_none().then_some(STACK_SIZE)
}
#[cfg(not(parallel_compiler))]
pub(crate) fn run_in_thread_pool_with_globals<F: FnOnce() -> R + Send, R: Send>(
pub(crate) fn run_in_thread_with_globals<F: FnOnce() -> R + Send, R: Send>(
edition: Edition,
_threads: usize,
f: F,
) -> R {
// The "thread pool" is a single spawned thread in the non-parallel
@ -171,18 +169,37 @@ pub(crate) fn run_in_thread_pool_with_globals<F: FnOnce() -> R + Send, R: Send>(
})
}
#[cfg(not(parallel_compiler))]
pub(crate) fn run_in_thread_pool_with_globals<F: FnOnce() -> R + Send, R: Send>(
edition: Edition,
_threads: usize,
f: F,
) -> R {
run_in_thread_with_globals(edition, f)
}
#[cfg(parallel_compiler)]
pub(crate) fn run_in_thread_pool_with_globals<F: FnOnce() -> R + Send, R: Send>(
edition: Edition,
threads: usize,
f: F,
) -> R {
use rustc_data_structures::jobserver;
use rustc_data_structures::{jobserver, sync::FromDyn};
use rustc_middle::ty::tls;
use rustc_query_impl::QueryCtxt;
use rustc_query_system::query::{deadlock, QueryContext};
let registry = sync::Registry::new(threads);
if !sync::is_dyn_thread_safe() {
return run_in_thread_with_globals(edition, || {
// Register the thread for use with the `WorkerLocal` type.
registry.register();
f()
});
}
let mut builder = rayon::ThreadPoolBuilder::new()
.thread_name(|_| "rustc".to_string())
.acquire_thread_handler(jobserver::acquire_thread)
@ -191,13 +208,13 @@ pub(crate) fn run_in_thread_pool_with_globals<F: FnOnce() -> R + Send, R: Send>(
.deadlock_handler(|| {
// On deadlock, creates a new thread and forwards information in thread
// locals to it. The new thread runs the deadlock handler.
let query_map = tls::with(|tcx| {
let query_map = FromDyn::from(tls::with(|tcx| {
QueryCtxt::new(tcx)
.try_collect_active_jobs()
.expect("active jobs shouldn't be locked in deadlock handler")
});
}));
let registry = rayon_core::Registry::current();
thread::spawn(move || deadlock(query_map, &registry));
thread::spawn(move || deadlock(query_map.into_inner(), &registry));
});
if let Some(size) = get_stack_size() {
builder = builder.stack_size(size);
@ -209,6 +226,7 @@ pub(crate) fn run_in_thread_pool_with_globals<F: FnOnce() -> R + Send, R: Send>(
// `Send` in the parallel compiler.
rustc_span::create_session_globals_then(edition, || {
rustc_span::with_session_globals(|session_globals| {
let session_globals = FromDyn::from(session_globals);
builder
.build_scoped(
// Initialize each new worker thread when created.
@ -216,7 +234,9 @@ pub(crate) fn run_in_thread_pool_with_globals<F: FnOnce() -> R + Send, R: Send>(
// Register the thread for use with the `WorkerLocal` type.
registry.register();
rustc_span::set_session_globals_then(session_globals, || thread.run())
rustc_span::set_session_globals_then(session_globals.into_inner(), || {
thread.run()
})
},
// Run `f` on the first thread in the thread pool.
move |pool: &rayon::ThreadPool| pool.install(f),