Add `slice::DrainRaw` for internal use #127348

scottmcm · 2024-07-05T00:42:33Z

I'd like to separate out this hopefully-non-controversial part of #124421 to have fewer commits to juggle there :)

Rather than encoding things as method calls or token expansions. This isn't directly useful for Iter/IterMut, but sets this up for the next commit that adds another invocation of the macro.

scottmcm · 2024-07-05T00:42:53Z

@bors try @rust-timer queue

bors · 2024-07-05T00:44:03Z

⌛ Trying commit 3f38556 with merge 2132470...

Add `slice::DrainRaw` for internal use I'd like to separate out this hopefully-non-controversial part of rust-lang#124421 to have fewer commits to juggle there :) r? `@the8472`

bors · 2024-07-05T02:26:12Z

☀️ Try build successful - checks-actions
Build commit: 2132470 (213247063d14960f8b256772f274b288657fb599)

rust-timer · 2024-07-05T07:59:29Z

Finished benchmarking commit (2132470): comparison URL.

Overall result: ❌✅ regressions and improvements - ACTION NEEDED

Benchmarking this pull request likely means that it is perf-sensitive, so we're automatically marking it as not fit for rolling up. While you can manually mark this PR as fit for rollup, we strongly recommend not doing so since this PR may lead to changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please indicate this with @rustbot label: +perf-regression-triaged along with sufficient written justification. If you cannot justify the regressions please fix the regressions and do another perf run. If the next run shows neutral or positive results, the label will be automatically removed.

@bors rollup=never
@rustbot label: -S-waiting-on-perf +perf-regression

Instruction count

This is a highly reliable metric that was used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	0.5%	[0.3%, 1.0%]	3
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.4%	[-0.7%, -0.3%]	3
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.0%	[-0.7%, 1.0%]	6

Max RSS (memory usage)

Results (primary 2.9%, secondary 0.0%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	4.1%	[2.0%, 7.3%]	8
Regressions ❌ (secondary)	0.8%	[0.7%, 0.8%]	2
Improvements ✅ (primary)	-2.3%	[-2.5%, -2.2%]	2
Improvements ✅ (secondary)	-0.7%	[-0.8%, -0.6%]	2
All ❌✅ (primary)	2.9%	[-2.5%, 7.3%]	10

Cycles

Results (primary 1.3%, secondary 0.7%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	1.3%	[1.3%, 1.3%]	1
Regressions ❌ (secondary)	1.4%	[0.6%, 2.2%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.7%	[-0.7%, -0.7%]	1
All ❌✅ (primary)	1.3%	[1.3%, 1.3%]	1

Binary size

Results (primary 0.0%, secondary -0.3%)

This is a less reliable metric that may be of interest but was not used to determine the overall result at the top of this comment.

	mean	range	count
Regressions ❌ (primary)	0.2%	[0.0%, 0.7%]	42
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.2%	[-0.7%, -0.1%]	17
Improvements ✅ (secondary)	-0.3%	[-0.8%, -0.1%]	6
All ❌✅ (primary)	0.0%	[-0.7%, 0.7%]	59

Bootstrap: 698.879s -> 701.919s (0.43%)
Artifact size: 328.27 MiB -> 328.37 MiB (0.03%)

the8472

Looks ok overall. The PR description could contain a bit of motivation, since that goes into the git history.

Also, I was not even aware of array::Drain. Once the alloc types get migrated that'll be more reasonable but right now it looks like quite a rube-goldberg machine to implement array::try_map 😅

the8472 · 2024-07-14T22:59:48Z

library/core/src/slice/drain.rs

This file contains a bunch of references to vec::IntoIter, with the current state that's confusing. Maybe refer to array::Drain instead?

the8472 · 2024-07-16T21:26:41Z

library/core/src/slice/drain.rs

+        let len = self.len();
+        let clamped = len.min(N);
+
+        // SAFETY: By construction, `clamped` is always in-bounds.
+        let to_copy = unsafe { self.0.skip_forward_unchecked(clamped) };
+        if len >= N {


Is the mix of len and clamped intentional?

the8472 · 2024-08-26T20:52:30Z

ping @scottmcm

JohnCSimon · 2024-11-29T05:42:24Z

@scottmcm
ping from triage - can you post your status on this PR? This PR has not received an update in a few months.

scottmcm · 2025-02-20T20:31:13Z

These have bitrotted enough that I'll close them as giving up on them for the foreseeeable future.

scottmcm added 4 commits July 4, 2024 17:03

Replace various iterator! parameters with self calls

bf4256a

Rather than encoding things as method calls or token expansions. This isn't directly useful for Iter/IterMut, but sets this up for the next commit that adds another invocation of the macro.

Add an internal slice::NonNullIter

8e8cac3

Add slice::DrainRaw that moves out of a NonNull<[T]>

8f0d4e3

Implement array::Drain using slice::DrainRaw

3f38556

rustbot assigned the8472 Jul 5, 2024

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-libs Relevant to the library team, which will review and decide on the PR/issue. labels Jul 5, 2024

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rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jul 5, 2024

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rustbot added perf-regression Performance regression. and removed S-waiting-on-perf Status: Waiting on a perf run to be completed. labels Jul 5, 2024

the8472 reviewed Jul 16, 2024

View reviewed changes

clarfonthey mentioned this pull request Aug 6, 2024

ACP: PtrRange<T> type rust-lang/libs-team#423

Closed

the8472 added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Aug 6, 2024

alex-semenyuk added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Sep 27, 2024

scottmcm closed this Feb 20, 2025

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Add `slice::DrainRaw` for internal use #127348

Add `slice::DrainRaw` for internal use #127348

scottmcm commented Jul 5, 2024

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scottmcm commented Feb 20, 2025

Add slice::DrainRaw for internal use #127348

Add slice::DrainRaw for internal use #127348

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rust-timer commented Jul 5, 2024

Overall result: ❌✅ regressions and improvements - ACTION NEEDED

Instruction count

Max RSS (memory usage)

Cycles

Binary size

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the8472 commented Aug 26, 2024

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scottmcm commented Feb 20, 2025

Add `slice::DrainRaw` for internal use #127348

Add `slice::DrainRaw` for internal use #127348