rustdoc: Fix performance regression for private documented items by GuillaumeGomez · Pull Request #164989 · rust-lang/rust

GuillaumeGomez · 2026-10-26T13:23:43Z

Should help with #161362.

The idea is to not (doc) inline private reexports by default. That will save us a lot of cleaning for external items and for html pages generation.

r? ghost

…fault

GuillaumeGomez · 2026-10-26T13:24:28Z

@bors try @rust-timer queue

rustdoc: Fix performance regression for private documented items

rust-bors · 2026-10-26T14:29:52Z

☀️ Try build successful (CI)
Build commit: 9ddb950 (9ddb950ce4342306fbe98df20021c4cc4ef6b29d)
Base parent: 019b59d (019b59d8101bb3e141f1b880684747b4217beeb6)

rust-timer · 2026-10-26T22:11:58Z

Finished benchmarking commit (9ddb950): comparison URL.

Overall result: ❌✅ regressions and improvements - please read:

Benchmarking means the PR may be perf-sensitive. Consider adding rollup=never if this change is not fit for rolling up.

Next, please: If you can, justify the regressions found in this try perf run in writing along with @rustbot label: +perf-regression-triaged. If not, fix the regressions and do another perf run. Neutral or positive results will clear the label automatically.

@bors rollup=iffy rustc-perf
@rustbot label: -S-waiting-on-perf +perf-regression

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	0.1%	[0.1%, 0.1%]	1
Improvements ✅ (primary)	-3.4%	[-5.1%, -1.8%]	2
Improvements ✅ (secondary)	-30.8%	[-59.9%, -1.8%]	2
All ❌✅ (primary)	-3.4%	[-5.1%, -1.8%]	2

Max RSS (memory usage)

Results (primary 0.2%, secondary 0.1%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	0.7%	[0.4%, 1.3%]	5
Regressions ❌ (secondary)	2.1%	[1.8%, 2.3%]	4
Improvements ✅ (primary)	-0.8%	[-1.4%, -0.4%]	3
Improvements ✅ (secondary)	-8.0%	[-8.0%, -8.0%]	1
All ❌✅ (primary)	0.2%	[-1.4%, 1.3%]	8

Cycles

Results (primary -0.9%, secondary -19.5%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	1.1%	[0.5%, 2.4%]	5
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-1.4%	[-3.3%, -0.4%]	20
Improvements ✅ (secondary)	-19.5%	[-52.9%, -2.7%]	3
All ❌✅ (primary)	-0.9%	[-3.3%, 2.4%]	25

Binary size

Results (secondary -0.0%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.0%	[-0.0%, -0.0%]	1
All ❌✅ (primary)	-	-	0

Bootstrap: 489.601s -> 488.841s (-0.16%)
Artifact size: 405.81 MiB -> 406.05 MiB (0.06%)

GuillaumeGomez · 2026-10-26T22:15:40Z

I have some ideas on how to improve it further but as a first step I think it's good enough.

r? @Urgau

Urgau · 2026-10-27T18:05:57Z

I don't have enough context to know all the implications of this change. r? rustdoc

notriddle · 2026-10-28T14:53:24Z

        };

-        let is_private = !self.cx.cache.effective_visibilities.is_directly_public(tcx, ori_res_did);
+        let is_private = (is_glob || !self.cx.document_private())


If you’re going to change what the variable means, change its name, too.

View changes since the review

Sure, done!

notriddle · 2026-10-29T20:07:20Z

@bors r+

rust-bors · 2026-10-29T20:07:23Z

📌 Commit ff245b9 has been approved by notriddle

It is now in the queue for this repository.

…-perf, r=notriddle rustdoc: Fix performance regression for private documented items Should help with rust-lang#161362. The idea is to not (doc) inline private reexports by default. That will save us a lot of `clean`ing for external items and for html pages generation. r? ghost

…uwer Rollup of 21 pull requests Successful merges: - #164851 (Add behavior tests for `Arc` and `Rc`) - #164989 (rustdoc: Fix performance regression for private documented items) - #165079 (Remove GenericArgRef) - #161781 (Don't emit InlineAsm terminator if input operand is `!`.) - #162754 (optimize large elements for slice rotating) - #163252 (Remove windows-targets dependency from the root workspace) - #163839 (Fix the floating point clobbers of RISC-V `clobber_abi`) - #165104 (Use getrandom instead of /scheme/rand on Redox OS) - #165132 (Implement `advance_back_by` on `Fuse`) - #165142 (Remove the unused generic Graphviz writer) - #163371 (Don't suggest replacing foreign format specifiers in `concat!` output) - #163802 (fix RegionEq direction in canonical query responses) - #163986 (omit unconditionally invoking crate level limits query) - #164920 (Point at prior token on `let` when expression is expected) - #164987 (use adt_async_drop_tys for nested ADTs in needs_async_drop) - #165061 (Use a fixed-length encoding for hash disambiguators in v0 symbols) - #165114 (use native interpreter impl for funnel shifts intrinsics) - #165119 (remove unnecessary fast path from borrowck) - #165122 (fix MaybeDangling validity logic for ZST at usize::MAX) - #165128 (Move `doc(keyword)` and `doc(attribute)` attributes checks from `rustc_passes` to `rustc_attr_parsing`) - #165129 (Fix ICE in prelude edition lint) Failed merges: - #164981 (Reflection add TypeId::name)

…-perf, r=notriddle rustdoc: Fix performance regression for private documented items Should help with rust-lang#161362. The idea is to not (doc) inline private reexports by default. That will save us a lot of `clean`ing for external items and for html pages generation. r? ghost

…uwer Rollup of 22 pull requests Successful merges: - #164851 (Add behavior tests for `Arc` and `Rc`) - #164989 (rustdoc: Fix performance regression for private documented items) - #165079 (Remove GenericArgRef) - #161781 (Don't emit InlineAsm terminator if input operand is `!`.) - #162754 (optimize large elements for slice rotating) - #163252 (Remove windows-targets dependency from the root workspace) - #163839 (Fix the floating point clobbers of RISC-V `clobber_abi`) - #165104 (Use getrandom instead of /scheme/rand on Redox OS) - #165132 (Implement `advance_back_by` on `Fuse`) - #165142 (Remove the unused generic Graphviz writer) - #165148 (ci: increase free disk space on macos-26 jobs) - #163371 (Don't suggest replacing foreign format specifiers in `concat!` output) - #163802 (fix RegionEq direction in canonical query responses) - #163986 (omit unconditionally invoking crate level limits query) - #164920 (Point at prior token on `let` when expression is expected) - #164987 (use adt_async_drop_tys for nested ADTs in needs_async_drop) - #165061 (Use a fixed-length encoding for hash disambiguators in v0 symbols) - #165114 (use native interpreter impl for funnel shifts intrinsics) - #165119 (remove unnecessary fast path from borrowck) - #165122 (fix MaybeDangling validity logic for ZST at usize::MAX) - #165128 (Move `doc(keyword)` and `doc(attribute)` attributes checks from `rustc_passes` to `rustc_attr_parsing`) - #165129 (Fix ICE in prelude edition lint) Failed merges: - #164981 (Reflection add TypeId::name) > [!WARNING] > This rollup conflicts with pending auto build #165205 and may need to be recreated if the pending build succeeds.

…uwer Rollup of 22 pull requests Successful merges: - #164851 (Add behavior tests for `Arc` and `Rc`) - #164989 (rustdoc: Fix performance regression for private documented items) - #165079 (Remove GenericArgRef) - #161781 (Don't emit InlineAsm terminator if input operand is `!`.) - #162754 (optimize large elements for slice rotating) - #163252 (Remove windows-targets dependency from the root workspace) - #163839 (Fix the floating point clobbers of RISC-V `clobber_abi`) - #165104 (Use getrandom instead of /scheme/rand on Redox OS) - #165132 (Implement `advance_back_by` on `Fuse`) - #165142 (Remove the unused generic Graphviz writer) - #165233 (Remove test-aarch64-apple-* jobs temporarily) - #163371 (Don't suggest replacing foreign format specifiers in `concat!` output) - #163802 (fix RegionEq direction in canonical query responses) - #163986 (omit unconditionally invoking crate level limits query) - #164920 (Point at prior token on `let` when expression is expected) - #164987 (use adt_async_drop_tys for nested ADTs in needs_async_drop) - #165061 (Use a fixed-length encoding for hash disambiguators in v0 symbols) - #165114 (use native interpreter impl for funnel shifts intrinsics) - #165119 (remove unnecessary fast path from borrowck) - #165122 (fix MaybeDangling validity logic for ZST at usize::MAX) - #165128 (Move `doc(keyword)` and `doc(attribute)` attributes checks from `rustc_passes` to `rustc_attr_parsing`) - #165129 (Fix ICE in prelude edition lint) > [!WARNING] > This rollup conflicts with pending auto build #165217 and may need to be recreated if the pending build succeeds.

Rollup merge of #164989 - GuillaumeGomez:rustdoc-doc-private-perf, r=notriddle rustdoc: Fix performance regression for private documented items Should help with #161362. The idea is to not (doc) inline private reexports by default. That will save us a lot of `clean`ing for external items and for html pages generation. r? ghost

rust-timer · 2026-10-31T21:03:47Z

Note

This PR was benchmarked as part of triage of its containing rollup: triage URL.

Finished benchmarking commit (9c3416d): comparison URL.

Overall result: ❌✅ regressions and improvements - please read:

Our benchmarks found a performance regression caused by this PR.
This might be an actual regression, but it can also be just noise.

Next Steps:

If the regression was expected or you think it can be justified,
please write a comment with sufficient written justification, and add
@rustbot label: +perf-regression-triaged to it, to mark the regression as triaged.
If you think that you know of a way to resolve the regression, try to create
a new PR with a fix for the regression.
If you do not understand the regression or you think that it is just noise,
you can ask the @rust-lang/wg-compiler-performance working group for help (members of this group
were already notified of this PR).

@rustbot label: +perf-regression
cc @rust-lang/wg-compiler-performance

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	0.2%	[0.2%, 0.2%]	4
Improvements ✅ (primary)	-1.1%	[-5.1%, -0.1%]	7
Improvements ✅ (secondary)	-30.8%	[-59.8%, -1.7%]	2
All ❌✅ (primary)	-1.1%	[-5.1%, -0.1%]	7

Max RSS (memory usage)

Results (secondary -3.3%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	1.9%	[1.9%, 1.9%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-8.5%	[-8.5%, -8.5%]	1
All ❌✅ (primary)	-	-	0

Cycles

Results (primary -3.8%, secondary -55.0%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-3.8%	[-3.8%, -3.8%]	1
Improvements ✅ (secondary)	-55.0%	[-55.0%, -55.0%]	1
All ❌✅ (primary)	-3.8%	[-3.8%, -3.8%]	1

Binary size

This perf run didn't have relevant results for this metric.

Artifact size: 406.61 MiB -> 406.77 MiB (0.04%)

…uwer Rollup of 22 pull requests Successful merges: - rust-lang/rust#164851 (Add behavior tests for `Arc` and `Rc`) - rust-lang/rust#164989 (rustdoc: Fix performance regression for private documented items) - rust-lang/rust#165079 (Remove GenericArgRef) - rust-lang/rust#161781 (Don't emit InlineAsm terminator if input operand is `!`.) - rust-lang/rust#162754 (optimize large elements for slice rotating) - rust-lang/rust#163252 (Remove windows-targets dependency from the root workspace) - rust-lang/rust#163839 (Fix the floating point clobbers of RISC-V `clobber_abi`) - rust-lang/rust#165104 (Use getrandom instead of /scheme/rand on Redox OS) - rust-lang/rust#165132 (Implement `advance_back_by` on `Fuse`) - rust-lang/rust#165142 (Remove the unused generic Graphviz writer) - rust-lang/rust#165233 (Remove test-aarch64-apple-* jobs temporarily) - rust-lang/rust#163371 (Don't suggest replacing foreign format specifiers in `concat!` output) - rust-lang/rust#163802 (fix RegionEq direction in canonical query responses) - rust-lang/rust#163986 (omit unconditionally invoking crate level limits query) - rust-lang/rust#164920 (Point at prior token on `let` when expression is expected) - rust-lang/rust#164987 (use adt_async_drop_tys for nested ADTs in needs_async_drop) - rust-lang/rust#165061 (Use a fixed-length encoding for hash disambiguators in v0 symbols) - rust-lang/rust#165114 (use native interpreter impl for funnel shifts intrinsics) - rust-lang/rust#165119 (remove unnecessary fast path from borrowck) - rust-lang/rust#165122 (fix MaybeDangling validity logic for ZST at usize::MAX) - rust-lang/rust#165128 (Move `doc(keyword)` and `doc(attribute)` attributes checks from `rustc_passes` to `rustc_attr_parsing`) - rust-lang/rust#165129 (Fix ICE in prelude edition lint) > [!WARNING] > This rollup conflicts with pending auto build #165217 and may need to be recreated if the pending build succeeds.

GuillaumeGomez added 2 commits October 26, 2026 14:22

rustdoc: Fix performance regression for private documented items

3b727ed

Add regression test to ensure private reexports are not inlined by de…

040d806

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rust-bors Bot pushed a commit that referenced this pull request Oct 26, 2026

Auto merge of #164989 - GuillaumeGomez:rustdoc-doc-private-perf, r=<try>

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rustdoc: Fix performance regression for private documented items

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rustbot assigned Urgau Oct 26, 2026

rustbot assigned notriddle and unassigned Urgau Oct 27, 2026

notriddle reviewed Oct 28, 2026

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rust-bors Bot added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Oct 29, 2026

JonathanBrouwer mentioned this pull request Oct 30, 2026

Rollup of 22 pull requests #165165

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JonathanBrouwer mentioned this pull request Oct 30, 2026

Rollup of 21 pull requests #165178

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JonathanBrouwer mentioned this pull request Oct 30, 2026

Rollup of 22 pull requests #165208

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Rollup of 22 pull requests #165234

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rust-bors Bot merged commit a935ff8 into rust-lang:main Oct 31, 2026
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rustbot added this to the 1.101.0 milestone Oct 31, 2026

rustbot added the perf-regression Performance regression. label Oct 31, 2026

GuillaumeGomez deleted the rustdoc-doc-private-perf branch November 1, 2026 20:38

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Overall result: ❌✅ regressions and improvements - please read:

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