Skip to content

Conversation

@scottmcm
Copy link
Member

This was a bad idea before, but now that size_of and align_of work completely differently than when removing it was first tried in 2020, maybe it makes sense now.

(Or maybe I'll just add another attempt to the list in the comments...)

r? ghost

@rustbot 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 Nov 19, 2025
@scottmcm
Copy link
Member Author

@bors try @rust-timer queue

@rust-timer

This comment has been minimized.

@rust-bors

This comment has been minimized.

rust-bors bot added a commit that referenced this pull request Nov 19, 2025
See if this is the time we can remove `layout::size_align`
@rustbot rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Nov 19, 2025
@rust-log-analyzer

This comment has been minimized.

This was a bad idea before, but now that `size_of` and `align_of` work completely differently than when removing it was first tried in 2020, maybe it makes sense now.

(Or maybe I'll just add another attempt to the list in the comments...)
@rust-bors
Copy link

rust-bors bot commented Nov 19, 2025

☀️ Try build successful (CI)
Build commit: 032b547 (032b5475d8c280e662d536ab2bb6b2f7f57a934e, parent: 07bdbaedc63094281483c40a88a1a8f2f8ffadc5)

@rust-timer

This comment has been minimized.

@rust-timer
Copy link
Collaborator

Finished benchmarking commit (032b547): comparison URL.

Overall result: ❌✅ regressions and improvements - please read the text below

Benchmarking this pull request means it may be perf-sensitive – we'll automatically label it not fit for rolling up. You can override this, but we strongly advise not to, due to possible changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please do so in sufficient writing along with @rustbot label: +perf-regression-triaged. If not, please fix the regressions and do another perf run. If its results are neutral or positive, the label will be automatically removed.

@bors rollup=never
@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)
1.1% [1.1%, 1.2%] 2
Improvements ✅
(primary)
- - 0
Improvements ✅
(secondary)
-0.7% [-1.3%, -0.1%] 10
All ❌✅ (primary) - - 0

Max RSS (memory usage)

Results (primary 3.9%)

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

mean range count
Regressions ❌
(primary)
3.9% [3.3%, 4.5%] 2
Regressions ❌
(secondary)
- - 0
Improvements ✅
(primary)
- - 0
Improvements ✅
(secondary)
- - 0
All ❌✅ (primary) 3.9% [3.3%, 4.5%] 2

Cycles

Results (primary -2.6%)

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)
-2.6% [-2.6%, -2.6%] 1
Improvements ✅
(secondary)
- - 0
All ❌✅ (primary) -2.6% [-2.6%, -2.6%] 1

Binary size

Results (primary -0.1%, 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)
0.0% [0.0%, 0.0%] 2
Regressions ❌
(secondary)
0.0% [0.0%, 0.0%] 1
Improvements ✅
(primary)
-0.2% [-0.4%, -0.0%] 23
Improvements ✅
(secondary)
- - 0
All ❌✅ (primary) -0.1% [-0.4%, 0.0%] 25

Bootstrap: 477.858s -> 472.077s (-1.21%)
Artifact size: 388.67 MiB -> 388.71 MiB (0.01%)

@rustbot rustbot added perf-regression Performance regression. and removed S-waiting-on-perf Status: Waiting on a perf run to be completed. labels Nov 19, 2025
@scottmcm scottmcm force-pushed the align-always-alignment branch from 2bf4c01 to 30f4a2a Compare November 20, 2025 06:09
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment

Labels

perf-regression Performance regression. 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.

Projects

None yet

Development

Successfully merging this pull request may close these issues.

4 participants