early return on duplicate span lowerings

[jdonszelmann]

@bors2 try

[jdonszelmann]

@bors2 try @rust-timer queue

[rust-timer]

This pull request was already queued before and is awaiting a try build to finish.

[rust-bors]

☀️ Try build successful (CI)
Build commit: a0c110f (a0c110f657f885a3fe1c9415cbffa402f2be5cb3, parent: f9e7961506a97b318ad4815b8ce94bb045562f89)

[rust-timer]

Finished benchmarking commit (a0c110f): 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)	0.1%	[0.1%, 0.1%]	2
Regressions ❌ (secondary)	0.2%	[0.2%, 0.2%]	7
Improvements ✅ (primary)	-0.8%	[-2.9%, -0.1%]	4
Improvements ✅ (secondary)	-0.6%	[-0.6%, -0.6%]	3
All ❌✅ (primary)	-0.5%	[-2.9%, 0.1%]	6

Max RSS (memory usage)

This benchmark run did not return any relevant results for this metric.

Cycles

Results (primary -2.4%, secondary 2.7%)

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)	2.7%	[2.7%, 2.7%]	1
Improvements ✅ (primary)	-2.4%	[-2.4%, -2.4%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-2.4%	[-2.4%, -2.4%]	1

Binary size

Results (primary -1.1%)

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)	-1.1%	[-1.1%, -1.1%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-1.1%	[-1.1%, -1.1%]	1

Bootstrap: 471.624s -> 473.081s (0.31%)
Artifact size: 388.73 MiB -> 388.78 MiB (0.01%)

[jdonszelmann]

welp, that seems worth it

[jdonszelmann]

lemme clean it up and mark it ready

[jdonszelmann]

r? @oli-obk

[rustbot]

oli-obk is not on the review rotation at the moment.
They may take a while to respond.

[WaffleLapkin]

@bors r+

[bors]

📌 Commit 0087253 has been approved by WaffleLapkin

It is now in the queue for this repository.

[bors]

⌛ Testing commit 0087253 with merge fa1f706...

[bors]

☀️ Test successful - checks-actions
Approved by: WaffleLapkin
Pushing fa1f706 to main...

[github-actions]

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 1d6c526 (parent) -> fa1f706 (this PR)

Test differences

Show 2 test diffs

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

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard fa1f706fbd0fd1c02763ecb28915bf23c860cb32 --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

1. aarch64-apple: 8994.2s -> 7065.9s (-21.4%)
2. dist-aarch64-apple: 6440.3s -> 7552.3s (+17.3%)
3. dist-x86_64-apple: 7541.4s -> 6608.8s (-12.4%)
4. i686-gnu-2: 5270.3s -> 5737.9s (+8.9%)
5. aarch64-gnu-llvm-20-2: 2315.4s -> 2116.6s (-8.6%)
6. test-various: 6542.9s -> 6042.8s (-7.6%)
7. x86_64-gnu: 6512.8s -> 7006.1s (+7.6%)
8. aarch64-msvc-1: 7198.3s -> 6662.3s (-7.4%)
9. dist-apple-various: 3671.0s -> 3909.5s (+6.5%)
10. pr-check-2: 2156.0s -> 2290.2s (+6.2%)

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]

Finished benchmarking commit (fa1f706): comparison URL.

Overall result: ❌ regressions - please read the text below

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)	0.3%	[0.1%, 0.8%]	70
Regressions ❌ (secondary)	0.4%	[0.0%, 0.8%]	73
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.3%	[0.1%, 0.8%]	70

Max RSS (memory usage)

Results (secondary -2.2%)

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)	-2.2%	[-2.2%, -2.2%]	1
All ❌✅ (primary)	-	-	0

Cycles

This benchmark run did not return any relevant results for this metric.

Binary size

Results (primary 0.0%, 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)	0.0%	[0.0%, 0.0%]	27
Regressions ❌ (secondary)	0.1%	[0.0%, 0.1%]	5
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.0%	[0.0%, 0.0%]	27

Bootstrap: 470.852s -> 468.293s (-0.54%)
Artifact size: 388.93 MiB -> 389.00 MiB (0.02%)

[nnethercote]

@jdonszelmann Final version results are very different to the original. Revert?

[jdonszelmann]

that's wild, I cannot imagine this to be anything but a perf improvement

[jdonszelmann]

are we sure this is accurate? I'm getting 502s (@Kobzol) on a bunch of the detailed pages

[jdonszelmann]

I guess I'll at least prep a revert yea

[Kobzol]

This master commit was used as the parent of a perf. run where I also benchmarked Cranelift (that causes the benchmark failures and the 502 links). However, the comment was created before that Cranelift run started, so I think that it should be the cause.

If you can create a revert and do a perf.run on it, that should confirm it.

[lqd]

Are the benchmark sets in production already? And if so, wouldn't they incur a period of noise while their significance thresholds adjust to the new collectors' behavior?

[Kobzol]

We still run only on one collector right now, the second is idle. (I want to change that today though 😅)

[panstromek]

perf triage:

Marking as triaged, based on the discussion above.

@rustbot label: +perf-regression-triaged