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.

Sign up for GitHub

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

perf test for removing some parallelism in encode_metadata #118496

Closed
wants to merge 2 commits into from
Closed

perf test for removing some parallelism in encode_metadata #118496

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
366a1b5
set default threads to 8
SparrowLii Dec 1, 2023
1880cdb
removing some parallelism
SparrowLii Dec 1, 2023
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
22 changes: 7 additions & 15 deletions compiler/rustc_metadata/src/rmeta/encoder.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -2193,21 +2193,13 @@ 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();

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) {
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));
}

let mut encoder = opaque::FileEncoder::new(path)
.unwrap_or_else(|err| tcx.sess.emit_fatal(FailCreateFileEncoder { err }));
encoder.emit_raw_bytes(METADATA_HEADER);
Expand Down
2 changes: 1 addition & 1 deletion compiler/rustc_session/src/options.rs
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -1897,7 +1897,7 @@ written to standard error output)"),
/// in the future. Note that -Zthreads=0 is the way to get
/// the num_cpus behavior.
#[rustc_lint_opt_deny_field_access("use `Session::threads` instead of this field")]
threads: usize = (1, parse_threads, [UNTRACKED],
threads: usize = (8, parse_threads, [UNTRACKED],
"use a thread pool with N threads"),
time_llvm_passes: bool = (false, parse_bool, [UNTRACKED],
"measure time of each LLVM pass (default: no)"),
Expand Down
Loading