move all mono-time checks into their own folder, and their own query #132843

RalfJung · 2024-11-10T11:13:00Z

The mono item collector currently also drives two mono-time checks: the lint for "large moves", and the check whether function calls are done with all the required target features.

Instead of doing this "inside" the collector, this PR refactors things so that we have a new rustc_monomorphize::mono_checks module providing a per-instance query that does these checks. We already have a per-instance query for the ABI checks, so this should be "free" for incremental builds. Non-incremental builds might do a bit more work now since we now have two separate MIR visits (in the collector and the mono-time checks) -- but one of them is cached in case the MIR doesn't change, which is nice.

This slightly changes behavior of the large-move check since the "move_size_spans" deduplication logic now only works per-instance, not globally across the entire collector.

Cc @saethlin since you're also doing some work related to queries and caching and monomorphization, though I don't know if there's any interaction here.

rustbot · 2024-11-10T11:13:08Z

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RalfJung · 2024-11-10T11:14:36Z

@bors try
@rust-timer queue

bors · 2024-11-10T11:15:46Z

⌛ Trying commit 23054c5 with merge 0c32858...

move all mono-time checks into their own folder, and their own query The mono item collector currently also drives two mono-time checks: the lint for "large moves", and the check whether function calls are done with all the required target features. Instead of doing this "inside" the collector, this PR refactors things so that we have a new `rustc_monomorphize::mono_checks` module providing a per-instance query that does these checks. We already have a per-instance query for the ABI checks, so this should be "free" for incremental builds. Non-incremental builds might do a bit more work now since we now have two separate MIR visits (in the collector and the mono-time checks) -- but one of them is cached in case the MIR doesn't change so that seems nice? This slightly changes behavior of the large-move check since the "move_size_spans" deduplication logic now only works per-instance, not globally across the entire collector. We could save some work by sharing the visitor between the ABI checks and the move checks, but let's see perf before doing that work. Cc `@saethlin` since you're also doing some work related to queries and caching and monomorphization, though I don't know if there's any interaction here.

bors · 2024-11-10T12:59:18Z

☀️ Try build successful - checks-actions
Build commit: 0c32858 (0c32858adbe120178078d89250910d237329c4e9)

rust-timer · 2024-11-10T14:25:10Z

Finished benchmarking commit (0c32858): 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

Instruction count

This is the most reliable metric that we have; it was used to determine the overall result at the top of this comment. However, even this metric can sometimes exhibit noise.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.2%	[-0.2%, -0.2%]	3
Improvements ✅ (secondary)	-0.3%	[-0.3%, -0.3%]	1
All ❌✅ (primary)	-0.2%	[-0.2%, -0.2%]	3

Max RSS (memory usage)

Results (primary 1.2%, secondary 4.6%)

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)	1.2%	[1.2%, 1.2%]	1
Regressions ❌ (secondary)	4.6%	[4.6%, 4.6%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	1.2%	[1.2%, 1.2%]	1

Cycles

Results (secondary 2.4%)

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)	3.6%	[3.3%, 4.2%]	4
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-2.2%	[-2.2%, -2.2%]	1
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 785.39s -> 786.581s (0.15%)
Artifact size: 335.26 MiB -> 335.38 MiB (0.04%)

RalfJung · 2024-11-10T14:54:01Z

That's not quite as much as I was hoping for given #132467, but even a neutral result is good news IMO since this cleans up the code. :)

RalfJung · 2024-11-10T15:20:08Z

@bors try
@rust-timer queue

bors · 2024-11-10T15:21:18Z

⌛ Trying commit f25b73b with merge 562f46b...

move all mono-time checks into their own folder, and their own query The mono item collector currently also drives two mono-time checks: the lint for "large moves", and the check whether function calls are done with all the required target features. Instead of doing this "inside" the collector, this PR refactors things so that we have a new `rustc_monomorphize::mono_checks` module providing a per-instance query that does these checks. We already have a per-instance query for the ABI checks, so this should be "free" for incremental builds. Non-incremental builds might do a bit more work now since we now have two separate MIR visits (in the collector and the mono-time checks) -- but one of them is cached in case the MIR doesn't change, which is nice. This slightly changes behavior of the large-move check since the "move_size_spans" deduplication logic now only works per-instance, not globally across the entire collector. Cc `@saethlin` since you're also doing some work related to queries and caching and monomorphization, though I don't know if there's any interaction here.

bors · 2024-11-10T17:06:25Z

☀️ Try build successful - checks-actions
Build commit: 562f46b (562f46ba55d4c1d3684c439eb0f048429f26b6be)

rust-timer · 2024-11-10T18:23:01Z

Finished benchmarking commit (562f46b): comparison URL.

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

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 the most reliable metric that we have; it was used to determine the overall result at the top of this comment. However, even this metric can sometimes exhibit noise.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	5.8%	[5.8%, 5.8%]	1
Improvements ✅ (primary)	-0.2%	[-0.2%, -0.2%]	1
Improvements ✅ (secondary)	-0.3%	[-0.3%, -0.3%]	1
All ❌✅ (primary)	-0.2%	[-0.2%, -0.2%]	1

Max RSS (memory usage)

Results (primary -2.3%, secondary 1.2%)

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)	4.0%	[3.0%, 5.1%]	2
Improvements ✅ (primary)	-2.3%	[-2.3%, -2.3%]	1
Improvements ✅ (secondary)	-4.3%	[-4.3%, -4.3%]	1
All ❌✅ (primary)	-2.3%	[-2.3%, -2.3%]	1

Cycles

Results (secondary 2.3%)

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
Regressions ❌ (secondary)	2.3%	[2.1%, 2.6%]	4
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 787.115s -> 786.126s (-0.13%)
Artifact size: 335.35 MiB -> 335.43 MiB (0.03%)

RalfJung · 2024-11-10T18:34:27Z

That actually makes things worse? What the heck? I thought doing fewer monomorphize calls and fewer mono_reachable traversals should help...

Ah well, I'll un-do the 2nd commit then.

saethlin · 2024-11-10T19:34:36Z

I don't think there is a significant difference between the two perf reports. The first one reports -0.21% on 3 primary benchmarks, and in the second, those results drop to -0.19%. Those are all incr-unchanged too.

The Detailed Results for the single regression point to time in LLVM and the linker as the cause, which doesn't make any sense. I'd bet that benchmark is just unstable.

RalfJung · 2024-11-10T19:47:17Z

Yeah, but my expectation was that this would help.

Though, thinking about it more... it can only help when the query gets executed. The affected primary benchmarks are all incr-unchanged, so the query doesn't even get executed. The commit should have helped with full or incr-full builds, but I guess there the entire query is not a measurable part of the overall runtime.

Keeping the visiting logic in the separate checks seems slightly cleaner to me (and avoids the visiting_function_call ugly hack), so with performance being equal, I prefer the first variant -- the one that is now in the PR. I can restore the other one though if you / the reviewer prefers that.

lcnr · 2024-11-11T13:52:18Z

compiler/rustc_monomorphize/src/mono_checks/move_check.rs

 }

-fn build_skip_move_check_fns(tcx: TyCtxt<'_>) -> Vec<DefId> {
+pub(crate) fn skip_move_check_fns(tcx: TyCtxt<'_>, _: ()) -> FxIndexSet<DefId> {


existing issue: but i feel like this should just be a diagnostics/rustc attribute on these methods 😅 having a builtin list here is quite meh

lcnr · 2024-11-11T13:52:32Z

@bors r+ rollup=never

bors · 2024-11-11T13:52:35Z

📌 Commit 23054c5 has been approved by lcnr

It is now in the queue for this repository.

bors · 2024-11-12T11:24:49Z

⌛ Testing commit 23054c5 with merge 583b25d...

bors · 2024-11-12T14:07:56Z

☀️ Test successful - checks-actions
Approved by: lcnr
Pushing 583b25d to master...

rust-timer · 2024-11-12T15:26:06Z

Finished benchmarking commit (583b25d): comparison URL.

Overall result: ✅ improvements - no action needed

@rustbot label: -perf-regression

Instruction count

This is the most reliable metric that we have; it was used to determine the overall result at the top of this comment. However, even this metric can sometimes exhibit noise.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.2%	[-0.2%, -0.2%]	4
Improvements ✅ (secondary)	-0.4%	[-0.4%, -0.4%]	1
All ❌✅ (primary)	-0.2%	[-0.2%, -0.2%]	4

Max RSS (memory usage)

Results (primary 0.1%, secondary -4.1%)

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)	3.3%	[3.3%, 3.3%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-1.5%	[-1.8%, -1.2%]	2
Improvements ✅ (secondary)	-4.1%	[-4.1%, -4.1%]	1
All ❌✅ (primary)	0.1%	[-1.8%, 3.3%]	3

Cycles

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

Binary size

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

Bootstrap: 784.209s -> 787.726s (0.45%)
Artifact size: 335.24 MiB -> 335.35 MiB (0.03%)

move all mono-time checks into their own folder, and their own query

23054c5

rustbot assigned lcnr Nov 10, 2024

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RalfJung mentioned this pull request Nov 10, 2024

perf experiment: disable large-move-check #132467

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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 Nov 10, 2024

RalfJung force-pushed the mono-time-checks branch from f25b73b to 23054c5 Compare November 10, 2024 18:35

lcnr reviewed Nov 11, 2024

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bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Nov 11, 2024

bors added the merged-by-bors This PR was explicitly merged by bors. label Nov 12, 2024

bors merged commit 583b25d into rust-lang:master Nov 12, 2024
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rustbot added this to the 1.84.0 milestone Nov 12, 2024

This was referenced Nov 12, 2024

MIR-only rlibs #119017

Draft

Querify MonoItem collection #132566

Open

ABI checks: add support for tier2 arches #132842

Open

rustbot removed the perf-regression Performance regression. label Nov 12, 2024

RalfJung deleted the mono-time-checks branch November 12, 2024 19:06

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move all mono-time checks into their own folder, and their own query #132843

move all mono-time checks into their own folder, and their own query #132843

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move all mono-time checks into their own folder, and their own query #132843

move all mono-time checks into their own folder, and their own query #132843

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Overall result: ✅ improvements - no action needed

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

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Overall result: ✅ improvements - no action needed

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