Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Revert "Change prefetch to avoid deadlock" #121910

Draft
wants to merge 1 commit into
base: master
Choose a base branch
from
Draft
Changes from all commits
Commits
File filter

Filter by extension

Filter by extension

Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
23 changes: 16 additions & 7 deletions compiler/rustc_metadata/src/rmeta/encoder.rs
Original file line number Diff line number Diff line change
Expand Up @@ -677,7 +677,8 @@ impl<'a, 'tcx> EncodeContext<'a, 'tcx> {
let debugger_visualizers =
stat!("debugger-visualizers", || self.encode_debugger_visualizers());

// Encode exported symbols info. This is prefetched in `encode_metadata`.
// Encode exported symbols info. This is prefetched in `encode_metadata` so we encode
// this as late as possible to give the prefetching as much time as possible to complete.
let exported_symbols = stat!("exported-symbols", || {
self.encode_exported_symbols(tcx.exported_symbols(LOCAL_CRATE))
});
Expand Down Expand Up @@ -2217,13 +2218,21 @@ pub fn encode_metadata(tcx: TyCtxt<'_>, path: &Path) {
// there's no need to do dep-graph tracking for any of it.
tcx.dep_graph.assert_ignored();

if tcx.sess.threads() != 1 {
// Prefetch some queries used by metadata encoding.
// This is not necessary for correctness, but is only done for performance reasons.
// It can be removed if it turns out to cause trouble or be detrimental to performance.
join(|| prefetch_mir(tcx), || tcx.exported_symbols(LOCAL_CRATE));
}
join(
|| encode_metadata_impl(tcx, path),
|| {
if tcx.sess.threads() == 1 {
return;
}
// Prefetch some queries used by metadata encoding.
// This is not necessary for correctness, but is only done for performance reasons.
// It can be removed if it turns out to cause trouble or be detrimental to performance.
join(|| prefetch_mir(tcx), || tcx.exported_symbols(LOCAL_CRATE));
},
);
}

fn encode_metadata_impl(tcx: TyCtxt<'_>, path: &Path) {
let mut encoder = opaque::FileEncoder::new(path)
.unwrap_or_else(|err| tcx.dcx().emit_fatal(FailCreateFileEncoder { err }));
encoder.emit_raw_bytes(METADATA_HEADER);
Expand Down
Loading