[perf] Cache the canonical instantiation of param-envs #142316

compiler-errors · 2025-06-10T21:48:47Z

r? lcnr

compiler-errors · 2025-06-10T21:48:56Z

@bors2 try @rust-timer queue

rust-bors · 2025-06-10T21:49:00Z

⌛ Trying commit 10849bc with merge 41eb046…

To cancel the try build, run the command @bors2 try cancel.

[perf] Cache the canonical *instantiation* of param-envs r? lcnr

rust-bors · 2025-06-11T00:15:45Z

☀️ Try build successful (CI)
Build commit: 41eb046 (41eb046262521d4f258e161c937b19a16cb53f37)

rust-timer · 2025-06-11T23:11:31Z

Finished benchmarking commit (41eb046): comparison URL.

Overall result: ✅ improvements - no action needed

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.

@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)	-	-	0
Improvements ✅ (primary)	-0.5%	[-0.9%, -0.1%]	18
Improvements ✅ (secondary)	-4.0%	[-20.1%, -0.1%]	19
All ❌✅ (primary)	-0.5%	[-0.9%, -0.1%]	18

Max RSS (memory usage)

Results (primary -1.9%)

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)	-1.9%	[-1.9%, -1.9%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-1.9%	[-1.9%, -1.9%]	1

Cycles

Results (primary -1.0%, secondary -7.8%)

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)	-1.0%	[-1.1%, -0.8%]	8
Improvements ✅ (secondary)	-7.8%	[-14.1%, -1.1%]	6
All ❌✅ (primary)	-1.0%	[-1.1%, -0.8%]	8

Binary size

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

Bootstrap: 755.415s -> 752.897s (-0.33%)
Artifact size: 372.14 MiB -> 372.01 MiB (-0.04%)

compiler-errors · 2025-06-11T23:17:02Z

Let's try this again w/o the "highest var in clauses" optimization.

compiler-errors · 2025-06-11T23:59:41Z

Let's try this but with highest_var_in_clauses not cached.

@bors2 try @rust-timer queue

rust-bors · 2025-06-11T23:59:45Z

⌛ Trying commit a74d247 with merge 98d94a4…

To cancel the try build, run the command @bors2 try cancel.

[perf] Cache the canonical *instantiation* of param-envs r? lcnr

rust-bors · 2025-06-12T02:27:27Z

☀️ Try build successful (CI)
Build commit: 98d94a4 (98d94a4710e69795b88dc65dc9526c47d10f54d6, parent: e703dff8fe220b78195c53478e83fb2f68d8499c)

rust-timer · 2025-06-12T07:47:05Z

Finished benchmarking commit (98d94a4): 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)	0.5%	[0.5%, 0.6%]	6
Regressions ❌ (secondary)	0.3%	[0.3%, 0.3%]	1
Improvements ✅ (primary)	-0.3%	[-0.6%, -0.1%]	13
Improvements ✅ (secondary)	-2.6%	[-15.9%, -0.1%]	24
All ❌✅ (primary)	-0.0%	[-0.6%, 0.6%]	19

Max RSS (memory usage)

Results (primary -3.5%)

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

	mean	range	count
Regressions ❌ (primary)	1.1%	[1.1%, 1.1%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-8.1%	[-8.1%, -8.1%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-3.5%	[-8.1%, 1.1%]	2

Cycles

Results (secondary -7.1%)

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
Improvements ✅ (secondary)	-7.1%	[-12.2%, -2.1%]	6
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 754.802s -> 754.047s (-0.10%)
Artifact size: 372.09 MiB -> 372.03 MiB (-0.02%)

lcnr · 2025-06-12T09:36:51Z

compiler/rustc_infer/src/infer/canonical/instantiate.rs

+    fn fold_clauses(&mut self, c: ty::Clauses<'tcx>) -> ty::Clauses<'tcx> {
+        if c.has_vars_bound_at_or_above(self.current_index) {
+            if self.current_index == ty::INNERMOST {
+                let index = highest_var_in_clauses(c);


instead have a separate Clauses -> usize hashmap in the tcx?

as in

pub instantiate_clauses_cache: Lock<( FxHashMap<ty::Clauses<'tcx>, usize>, FxHashMap<(ty::Clauses<'tcx>, &'tcx [ty::GenericArg<'tcx>]), ty::Clauses<'tcx>>) >,

that was the previous perf run

ah 😅 👍 u just too smart

specifically i was double checking that the caching of the max var in the clauses was worth it, and it seems like it is

rustbot assigned lcnr Jun 10, 2025

rustbot added the T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. label Jun 10, 2025

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rust-bors bot added a commit that referenced this pull request Jun 10, 2025

Auto merge of #142316 - compiler-errors:cache-param-env, r=<try>

41eb046

[perf] Cache the canonical *instantiation* of param-envs r? lcnr

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jun 10, 2025

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rustbot removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jun 11, 2025

compiler-errors force-pushed the cache-param-env branch from 10849bc to a74d247 Compare June 11, 2025 23:59

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rust-bors bot added a commit that referenced this pull request Jun 11, 2025

Auto merge of #142316 - compiler-errors:cache-param-env, r=<try>

98d94a4

[perf] Cache the canonical *instantiation* of param-envs r? lcnr

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jun 11, 2025

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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 Jun 12, 2025

lcnr reviewed Jun 12, 2025

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835662b

compiler-errors force-pushed the cache-param-env branch from a74d247 to 835662b Compare June 12, 2025 13:31

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[perf] Cache the canonical instantiation of param-envs #142316

[perf] Cache the canonical instantiation of param-envs #142316

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lcnr Jun 12, 2025 •

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[perf] Cache the canonical *instantiation* of param-envs #142316

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rust-timer commented Jun 11, 2025

Overall result: ✅ improvements - no action needed

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

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[perf] Cache the canonical instantiation of param-envs #142316

[perf] Cache the canonical instantiation of param-envs #142316

lcnr Jun 12, 2025 •

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