Change LLVM BOLT flags by Kobzol · Pull Request #114141 · rust-lang/rust · GitHu...

added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-bootstrap Relevant to the bootstrap subteam: Rust's build system (x.py and src/bootstrap)

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Jul 27, 2023

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added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label

Jul 27, 2023

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⌛ Trying commit bc6b5fe with merge b734abf...

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Try build successful - checks-actions
Build commit: b734abf (b734abfa73b23b4b0db768de4dba2901bca0ead5)

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src/bootstrap/bolt.rs

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		// Try to reuse old text segments to reduce binary size
		.arg("--use-old-text")
		.arg("--lite=0")
		.arg("--no-huge-pages")

I assume the huge page alignment just adds padding, so it should compress fine and not affect download sizes and also shouldn't affect the amount of stuff that gets loaded into memory.

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I'm not actually sure what this does, as it seems to be undocumented. I'll try without it.

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Finished benchmarking commit (b734abf): comparison URL.

Overall result: regressions and 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 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)	0.7%	[0.3%, 1.1%]	4
Improvements (primary)	-	-	0
Improvements (secondary)	-0.3%	[-0.3%, -0.3%]	1
All (primary)	-	-	0

Max RSS (memory usage)

Results

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: 654.227s -> 655.834s (0.25%)

removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label

Jul 28, 2023

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Okay, pretty much no regressions and -50 MiB of LLVM size. Pretty nice. I'll try next what happens with just --use-old-text.

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@bors try @rust-timer queue

Trying just --use-old-text.

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added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label

Jul 28, 2023

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Trying commit b996e5e with merge b5ad006...

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Try build successful - checks-actions
Build commit: b5ad006 (b5ad0060faf5ff61111a1a191fe848f4955ac46f)

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Finished benchmarking commit (b5ad006): comparison URL.

Overall result: improvements - no action needed

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

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)	-0.4%	[-0.4%, -0.4%]	1
Improvements ✅ (secondary)	-	-	0
All (primary)	-0.4%	[-0.4%, -0.4%]	1

Max RSS (memory usage)

Results

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: 651.183s -> 650.167s (-0.16%)

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removed the S-waiting-on-perf Status: Waiting on a perf run to be completed. label

Kobzol

marked this pull request as ready for review

July 29, 2023 08:52

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Ok, looks like adding this flag doesn't regress perf and saves 50 MiB of libLLVM size. That looks nice.

r? bootstrap

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@bors r+

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📌 Commit b996e5e has been approved by lqd

It is now in the queue for this repository.

removed the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label

added the S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. label

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Author

BOLT can be tricky, so let's make sure that this is easier to revert if some issuea crop up.

@bors rollup=never

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Testing commit b996e5e with merge f45961b...

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☀️ Test successful - checks-actions
Approved by: lqd
Pushing f45961b to master...

added the merged-by-bors This PR was explicitly merged by bors label

merged commit f45961b into

rust-lang:master