[perf] test MCP510 by lqd · Pull Request #113382 · rust-lang/rust

lqd · 2023-07-05T20:17:41Z

rust-timer · 2023-07-05T23:34:04Z

Finished benchmarking commit (4cb98396e9dc17fbe9b0da2b1bd35d9b05fff30c): comparison URL.

Overall result: ✅ improvements - no 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.

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

Warning ⚠: The following benchmark(s) failed to build:

rustc

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
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-34.1%	[-74.8%, -0.6%]	31
Improvements ✅ (secondary)	-32.7%	[-74.0%, -3.7%]	74
All ❌✅ (primary)	-34.1%	[-74.8%, -0.6%]	31

Max RSS (memory usage)

Results

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)	27.8%	[21.9%, 33.7%]	2
Regressions ❌ (secondary)	2.3%	[2.3%, 2.3%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	27.8%	[21.9%, 33.7%]	2

Cycles

Results

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
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-32.3%	[-65.9%, -1.4%]	28
Improvements ✅ (secondary)	-28.4%	[-64.8%, -3.3%]	73
All ❌✅ (primary)	-32.3%	[-65.9%, -1.4%]	28

Binary size

Results

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)	1.6%	[0.6%, 2.4%]	20
Regressions ❌ (secondary)	0.5%	[0.4%, 1.1%]	61
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.3%	[-0.4%, -0.1%]	2
All ❌✅ (primary)	1.6%	[0.6%, 2.4%]	20

Bootstrap: missing data

lqd · 2023-07-18T17:42:43Z

The data gathering is done so I'll close this for now, but may reopen to rerun crater on these new try artifacts.

rust-bors · 2025-12-09T16:36:00Z

☀️ Try build successful (CI)
Build commit: 621e94b (621e94b4dbb812275cb66899eed6f57ccd49ea3e, parent: d5525a73009e2c61b09daa69df79064530bd4dcf)

rust-timer · 2025-12-09T17:55:55Z

Finished benchmarking commit (621e94b): 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)	3.0%	[0.2%, 16.2%]	96
Regressions ❌ (secondary)	1.9%	[0.1%, 15.7%]	112
Improvements ✅ (primary)	-0.4%	[-0.6%, -0.2%]	7
Improvements ✅ (secondary)	-0.3%	[-1.0%, -0.0%]	21
All ❌✅ (primary)	2.7%	[-0.6%, 16.2%]	103

Max RSS (memory usage)

Results (primary 11.0%, secondary 5.0%)

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

	mean	range	count
Regressions ❌ (primary)	12.5%	[0.8%, 29.7%]	9
Regressions ❌ (secondary)	11.4%	[0.7%, 43.3%]	15
Improvements ✅ (primary)	-2.1%	[-2.1%, -2.1%]	1
Improvements ✅ (secondary)	-3.8%	[-7.3%, -1.1%]	11
All ❌✅ (primary)	11.0%	[-2.1%, 29.7%]	10

Cycles

Results (primary 4.5%, secondary 4.9%)

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

	mean	range	count
Regressions ❌ (primary)	4.9%	[2.1%, 9.2%]	18
Regressions ❌ (secondary)	4.9%	[1.9%, 7.4%]	28
Improvements ✅ (primary)	-2.5%	[-2.5%, -2.5%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	4.5%	[-2.5%, 9.2%]	19

Binary size

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

Bootstrap: 472.272s -> 473.236s (0.20%)
Artifact size: 389.04 MiB -> 386.94 MiB (-0.54%)

now that the analysis is only using the regular liveness shape, we don't need to store it transposed, and thus don't need the container where it was stored: the liveness context would be alone in the polonius context. we thus remove the latter, and rename the former.

we may need to traverse the lazy graph multiple times: - to record loan liveness - to dump the localized outlives constraint in the polonius MIR dump to do that we extract the previous loan liveness code into an abstract traversal + visitor handling the liveness-specific parts, while the MIR dump will be able to record constraints in its own visitor.

now that we need to hold the graph for MIR dumping, and the associated data to traverse it, there is no difference between the main context and diagnostics context, so we merge them.

lqd · 2026-01-07T10:18:29Z

note to self about the experiment: "finalized lazy construction of the polonius localized constraints, -Zpolonius=next enabled so tests will fail"

@bors try @rust-timer queue

[perf] test MCP510

rust-timer · 2026-01-07T13:23:35Z

Finished benchmarking commit (a1558d5): 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)	2.7%	[0.1%, 14.9%]	97
Regressions ❌ (secondary)	1.7%	[0.1%, 14.5%]	117
Improvements ✅ (primary)	-0.2%	[-0.3%, -0.2%]	3
Improvements ✅ (secondary)	-0.4%	[-0.6%, -0.2%]	12
All ❌✅ (primary)	2.6%	[-0.3%, 14.9%]	100

Max RSS (memory usage)

Results (primary 3.2%, secondary 2.0%)

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

	mean	range	count
Regressions ❌ (primary)	4.6%	[2.0%, 7.5%]	6
Regressions ❌ (secondary)	5.1%	[0.9%, 12.2%]	6
Improvements ✅ (primary)	-0.9%	[-0.9%, -0.8%]	2
Improvements ✅ (secondary)	-4.2%	[-4.9%, -3.7%]	3
All ❌✅ (primary)	3.2%	[-0.9%, 7.5%]	8

Cycles

Results (primary 4.4%, secondary 4.4%)

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

	mean	range	count
Regressions ❌ (primary)	4.4%	[2.1%, 8.7%]	27
Regressions ❌ (secondary)	4.4%	[1.9%, 6.9%]	23
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	4.4%	[2.1%, 8.7%]	27

Binary size

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

Bootstrap: 474.542s -> 476.053s (0.32%)
Artifact size: 390.84 MiB -> 390.59 MiB (-0.06%)

rust-bors · 2026-01-23T14:10:19Z

☔ The latest upstream changes (presumably #151533) made this pull request unmergeable. Please resolve the merge conflicts.

Allow target specs to use an LLD flavor, and self-contained linking components This PR allows: - target specs to use an LLD linker-flavor: this is needed to switch `x86_64-unknown-linux-gnu` to using LLD, and is currently not possible because the current flavor json serialization fails to roundtrip on the modern linker-flavors. This can e.g. be seen in rust-lang/rust#115622 (comment) which explains where an `Lld::Yes` is ultimately deserialized into an `Lld::No`. - target specs to declare self-contained linking components: this is needed to switch `x86_64-unknown-linux-gnu` to using `rust-lld` - adds an end-to-end test of a custom target json simulating `x86_64-unknown-linux-gnu` being switched to using `rust-lld` - disables codegen backends from participating because they don't support `-Zgcc-ld=lld` which is the basis of mcp510. r? `@petrochenkov:` if the approach discussed rust-lang/rust#115622 (comment) and on zulip would work for you: basically, see if we can emit only modern linker flavors in the json specs, but accept both old and new flavors while reading them, to fix the roundtrip issue. The backwards compatible `LinkSelfContainedDefault` variants are still serialized and deserialized in `crt-objects-fallback`, while the spec equivalent of e.g. `-Clink-self-contained=+linker` is serialized into a different json object (with future-proofing to incorporate `crt-objects-fallback` in the future). --- I've been test-driving this in rust-lang/rust#113382 to test actually switching `x86_64-unknown-linux-gnu` to `rust-lld` (and fix what needs to be fixed in CI, bootstrap, etc), and it seems to work fine.

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Jul 5, 2023

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rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jul 5, 2023

lqd closed this Jul 18, 2023

lqd reopened this Sep 12, 2023

lqd force-pushed the test-mcp510 branch from 793c8e6 to a9e047f Compare September 12, 2023 15:38

rustbot added the T-bootstrap Relevant to the bootstrap subteam: Rust's build system (x.py and src/bootstrap) label Sep 12, 2023

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lqd force-pushed the test-mcp510 branch from a9e047f to 68e4f7d Compare September 12, 2023 17:25

lqd force-pushed the test-mcp510 branch from 68e4f7d to fb7cde3 Compare September 20, 2023 17:39

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lqd force-pushed the test-mcp510 branch from fb7cde3 to 3adfc22 Compare September 20, 2023 17:47

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lqd force-pushed the test-mcp510 branch from 3adfc22 to df25e9c Compare September 20, 2023 18:04

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lqd force-pushed the test-mcp510 branch from df25e9c to 03e476e Compare September 20, 2023 19:19

lqd closed this Sep 20, 2023

lqd reopened this Sep 21, 2023

lqd force-pushed the test-mcp510 branch from 03e476e to 5e67656 Compare September 21, 2023 18:31

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lqd force-pushed the test-mcp510 branch from 4fb2d00 to 3febecf Compare December 9, 2025 14:29

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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 Dec 9, 2025

lqd added 9 commits December 29, 2025 23:38

introduce lazy traversal for the polonius constraint graph

eb3b5a2

remove eager constraint conversion

a4270ff

optimization: no need to convert liveness data shape anymore

5ac2edf

optimization: do nothing if there are no loans

f95fd9a

adapt polonius MIR dump to lazy graph traversal

51b0292

merge remaining contexts

99dab0a

now that we need to hold the graph for MIR dumping, and the associated data to traverse it, there is no difference between the main context and diagnostics context, so we merge them.

tmp: set polonius=next by default

024b753

lqd force-pushed the test-mcp510 branch from 3febecf to 024b753 Compare January 7, 2026 10:16

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rust-bors bot added a commit that referenced this pull request Jan 7, 2026

Auto merge of #113382 - lqd:test-mcp510, r=<try>

a1558d5

[perf] test MCP510

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jan 7, 2026

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rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jan 7, 2026

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rust-timer commented Jul 5, 2023

Overall result: ✅ improvements - no action needed

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rust-timer commented Dec 9, 2025

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

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rust-timer commented Jan 7, 2026

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

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