Rollup of 3 pull requests by matthiaskrgr · Pull Request #149581 · rust-lang/rust

matthiaskrgr · 2025-12-03T06:36:15Z

Successful merges:

Remove initialized-bytes tracking from BorrowedBuf and BorrowedCursor #148937 (Remove initialized-bytes tracking from BorrowedBuf and BorrowedCursor)
added default_uwtables=true to aarch64_unknown_none targets #149553 (added default_uwtables=true to aarch64_unknown_none targets)
rustdoc: Fix broken link to Itertools::format #149578 (rustdoc: Fix broken link to Itertools::format)

r? @ghost
@rustbot modify labels: rollup

…sor` As discussed extensively in libs-api, the initialized-bytes tracking primarily benefits calls to `read_buf` that end up initializing the buffer and calling `read`, at the expense of calls to `read_buf` that *don't* need to initialize the buffer. Essentially, this optimizes for the past at the expense of the future. If people observe performance issues using `read_buf` (or something that calls it) with a given `Read` impl, they can fix those performance issues by implementing `read_buf` for that `Read`. Update the documentation to stop talking about initialized-but-unfilled bytes. Remove all functions that just deal with those bytes and their tracking, and remove usage of those methods. Remove `BorrowedCursor::advance` as there's no longer a safe case for advancing within initialized-but-unfilled bytes. Rename `BorrowedCursor::advance_unchecked` to `advance`. Update tests.

…tracking, r=Amanieu Remove initialized-bytes tracking from `BorrowedBuf` and `BorrowedCursor` As discussed extensively in libs-api, the initialized-bytes tracking primarily benefits calls to `read_buf` that end up initializing the buffer and calling `read`, at the expense of calls to `read_buf` that *don't* need to initialize the buffer. Essentially, this optimizes for the past at the expense of the future. If people observe performance issues using `read_buf` (or something that calls it) with a given `Read` impl, they can fix those performance issues by implementing `read_buf` for that `Read`. Update the documentation to stop talking about initialized-but-unfilled bytes. Remove all functions that just deal with those bytes and their tracking, and remove usage of those methods. Remove `BorrowedCursor::advance` as there's no longer a safe case for advancing within initialized-but-unfilled bytes. Rename `BorrowedCursor::advance_unchecked` to `advance`. Update tests. r? ``@Amanieu``

…efault-uwtables, r=wesleywiser added default_uwtables=true to aarch64_unknown_none targets This patch adds DWARF unwinding tables by default for `aarch64-unknown-none` and `aarch64-unknown-none-softfloat` targets. By implication, the `core` library for these targets will be built with unwinding tables. These tables are often useful, and are especially needed for backtracing through `core` on embedded targets. The tables can be turned off for user compilation with `-C force-unwind-tables=no` if desired. (I am the lead maintainer for these targets in the Rust Embedded Working Group, and have discussed this with REWG.)

…=notriddle rustdoc: Fix broken link to `Itertools::format` close rust-lang#148879

matthiaskrgr · 2025-12-03T06:36:26Z

@bors r+ rollup=never p=5

bors · 2025-12-03T06:36:28Z

📌 Commit 7432e9e has been approved by matthiaskrgr

It is now in the queue for this repository.

bors · 2025-12-03T06:36:29Z

🌲 The tree is currently closed for pull requests below priority 1000. This pull request will be tested once the tree is reopened.

matthiaskrgr · 2025-12-03T06:43:28Z

@bors treeclosed-

bors · 2025-12-03T06:44:38Z

⌛ Testing commit 7432e9e with merge 254ed0a...

Rollup of 3 pull requests Successful merges: - #148937 (Remove initialized-bytes tracking from `BorrowedBuf` and `BorrowedCursor`) - #149553 (added default_uwtables=true to aarch64_unknown_none targets) - #149578 (rustdoc: Fix broken link to `Itertools::format`) r? `@ghost` `@rustbot` modify labels: rollup

rust-log-analyzer · 2025-12-03T07:27:51Z

The job x86_64-gnu-tools failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

matthiaskrgr · 2025-12-03T07:29:28Z

@/bors treeclosed=1000

matthiaskrgr · 2025-12-03T07:32:54Z

@bors retry

matthiaskrgr · 2025-12-03T07:55:02Z

@\bors treeclosed-

bors · 2025-12-03T07:56:12Z

⌛ Testing commit 7432e9e with merge 8202d11...

bors · 2025-12-03T12:03:33Z

☀️ Test successful - checks-actions
Approved by: matthiaskrgr
Pushing 8202d11 to main...

rust-timer · 2025-12-03T12:04:29Z

📌 Perf builds for each rolled up PR:

PR#	Message	Perf Build Sha
#148937	Remove initialized-bytes tracking from `BorrowedBuf` and `B…	`cbe97c4856783c3f077b83b98a6dcf7c92a8e637` (link)
#149553	added default_uwtables=true to aarch64_unknown_none targets	`fabdbd0fa380d12bab07e9e16465aab514956fe0` (link)
#149578	rustdoc: Fix broken link to `Itertools::format`	`a9a31814567301b8be5c329e94e534996dfbad56` (link)

previous master: 672388edbe

In the case of a perf regression, run the following command for each PR you suspect might be the cause: @rust-timer build $SHA

github-actions · 2025-12-03T12:06:37Z

What is this?

This is an experimental post-merge analysis report that shows differences in test outcomes between the merged PR and its parent PR.

Comparing 672388e (parent) -> 8202d11 (this PR)

Test differences

Show 212 test diffs

Stage 1

io::borrowed_buf::cursor_set_init: pass -> [missing] (J0)
io::borrowed_buf::initialize_unfilled: pass -> [missing] (J0)
io::borrowed_buf::set_init: pass -> [missing] (J0)
io::buffered::tests::bufreader_full_initialize: pass -> [missing] (J2)
io::tests::borrowed_cursor_advance_overflow: pass -> [missing] (J2)

Stage 2

io::borrowed_buf::cursor_set_init: pass -> [missing] (J1)
io::borrowed_buf::initialize_unfilled: pass -> [missing] (J1)
io::borrowed_buf::set_init: pass -> [missing] (J1)
io::buffered::tests::bufreader_full_initialize: pass -> [missing] (J1)
io::tests::borrowed_cursor_advance_overflow: pass -> [missing] (J1)

Additionally, 202 doctest diffs were found. These are ignored, as they are noisy.

Job group index

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard 8202d110516c6bd87cee375e9a9b774db499015c --output-dir test-dashboard

And then open test-dashboard/index.html in your browser to see an overview of all executed tests.

Job duration changes

i686-msvc-1: 10599.7s -> 14259.1s (+34.5%)
dist-apple-various: 4600.2s -> 3588.7s (-22.0%)
aarch64-apple: 9909.4s -> 8410.4s (-15.1%)
test-various: 6892.4s -> 5960.2s (-13.5%)
x86_64-gnu-llvm-20: 2236.4s -> 2478.2s (+10.8%)
x86_64-msvc-ext1: 7879.6s -> 7080.1s (-10.1%)
i686-gnu-nopt-2: 8059.2s -> 7317.1s (-9.2%)
x86_64-gnu-aux: 7188.2s -> 6583.2s (-8.4%)
x86_64-gnu-miri: 4393.1s -> 4034.5s (-8.2%)
dist-x86_64-apple: 7419.3s -> 8017.0s (+8.1%)

How to interpret the job duration changes?

Job durations can vary a lot, based on the actual runner instance
that executed the job, system noise, invalidated caches, etc. The table above is provided
mostly for t-infra members, for simpler debugging of potential CI slow-downs.

rust-timer · 2025-12-03T13:23:52Z

Finished benchmarking commit (8202d11): comparison URL.

Overall result: ❌✅ regressions and improvements - no action needed

@rustbot label: -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)	-0.1%	[-0.1%, -0.1%]	1
Improvements ✅ (secondary)	-0.2%	[-0.2%, -0.1%]	2
All ❌✅ (primary)	-0.1%	[-0.1%, -0.1%]	1

Max RSS (memory usage)

Results (primary -0.5%)

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

	mean	range	count
Regressions ❌ (primary)	3.1%	[3.1%, 3.1%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-4.1%	[-4.1%, -4.1%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-0.5%	[-4.1%, 3.1%]	2

Cycles

Results (primary 2.4%, secondary -4.3%)

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

	mean	range	count
Regressions ❌ (primary)	2.4%	[2.4%, 2.4%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-4.3%	[-7.7%, -2.5%]	3
All ❌✅ (primary)	2.4%	[2.4%, 2.4%]	1

Binary size

Results (primary -0.3%, 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
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.3%	[-1.3%, -0.0%]	6
Improvements ✅ (secondary)	-0.1%	[-0.1%, -0.1%]	1
All ❌✅ (primary)	-0.3%	[-1.3%, -0.0%]	6

Bootstrap: 469.113s -> 469.504s (0.08%)
Artifact size: 386.77 MiB -> 386.76 MiB (-0.00%)

kamulos · 2025-12-05T10:35:58Z

The Runtime (cycles) looks strange for this 🤔

joshtriplett and others added 7 commits December 2, 2025 01:32

Update other targets for BorrowedCursor unstable API changes

1ef636d

added default_uwtables=true to aarch64_unknown_none targets

48002fc

rustdoc: Fix broken link to Itertools::format

8949b81

Rollup merge of rust-lang#149578 - lapla-cogito:rustdoc_iterformat, r…

7432e9e

…=notriddle rustdoc: Fix broken link to `Itertools::format` close rust-lang#148879

bors 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 Dec 3, 2025

matthiaskrgr mentioned this pull request Dec 3, 2025

src/doc/reference doctests is failing in PR CI #149575

Closed

bors mentioned this pull request Dec 3, 2025

Fix std::mem::drop rustdoc misleading statement #149244

Merged

bors added the merged-by-bors This PR was explicitly merged by bors. label Dec 3, 2025

bors merged commit 8202d11 into rust-lang:main Dec 3, 2025
6 of 12 checks passed

rustbot added this to the 1.93.0 milestone Dec 3, 2025

This was referenced Dec 3, 2025

std: reorganize pipe implementations #146794

Merged

std: Use more unix.rs code on WASI targets #147572

Merged

Add support for xray in aarch64 unknown none target #148666

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Test differences

Stage 1

Stage 2

Job duration changes

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rust-timer commented Dec 3, 2025

Overall result: ❌✅ regressions and improvements - no action needed

Instruction count

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Cycles

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