(EXPERIMENT) Perf experiments for target-machine command-line quoting

[Zalathar]

This works because the only characters we care about escaping are ASCII characters, so forwarding non-ASCII UTF-8 bytes as-is still produces correct results.

r? ghost

[Zalathar]

@bors try @rust-timer queue

[rust-bors]

☀️ Try build successful (CI)
Build commit: 515de9c (515de9cd3470057d08f216bc055bf2a2236db0c0, parent: ec38671075266e9cee0348701da2e133379e7c6c)

[rust-timer]

Finished benchmarking commit (515de9c): 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
Improvements ✅ (secondary)	-1.7%	[-8.2%, -0.3%]	8
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

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

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: 470.599s -> 471.807s (0.26%)
Artifact size: 389.97 MiB -> 389.89 MiB (-0.02%)

[Zalathar]

I'm going to recycle this PR for a few related perf experiments.

Ironically, benchmarking these changes is only possible because we prepare quoted command-line arguments for all targets, even though the string only gets used for generating PDBs.

@bors try @rust-timer queue

[Zalathar]

There's a more general problem that producing this command-line string makes target_machine_factory relatively expensive, but there are a few callers that treat it as cheap.

It would be nice to build the string at most once per rustc, but we'd have to figure out where to put the necessary mutable state.

[rust-bors]

☀️ Try build successful (CI)
Build commit: 09a6b1d (09a6b1dbdadd53e80e5fc085caefd7d23daf7793, parent: e4b521903b3b1a671e26a70b9475bcff385767e5)

[rust-timer]

Finished benchmarking commit (09a6b1d): 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)	-0.3%	[-0.3%, -0.2%]	3
Improvements ✅ (secondary)	-1.5%	[-9.2%, -0.3%]	11
All ❌✅ (primary)	-0.3%	[-0.3%, -0.2%]	3

Max RSS (memory usage)

Results (primary 0.9%, secondary 3.4%)

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

	mean	range	count
Regressions ❌ (primary)	1.8%	[0.8%, 2.4%]	3
Regressions ❌ (secondary)	3.4%	[3.4%, 3.4%]	1
Improvements ✅ (primary)	-1.7%	[-1.7%, -1.7%]	1
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	0.9%	[-1.7%, 2.4%]	4

Cycles

Results (secondary -2.5%)

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)	-2.5%	[-2.5%, -2.5%]	1
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 472.018s -> 473.009s (0.21%)
Artifact size: 389.98 MiB -> 389.96 MiB (-0.00%)

[rustbot]

This PR was rebased onto a different master commit. Here's a range-diff highlighting what actually changed.

Rebasing is a normal part of keeping PRs up to date, so no action is needed—this note is just to help reviewers.

[Zalathar]

@bors try @rust-timer queue

[rust-bors]

☀️ Try build successful (CI)
Build commit: 3cad4c1 (3cad4c1f7f06414cb89aa67750ddd77153f59100, parent: 9f32ccf35fb877270bc44a86a126440f04d676d0)

[rust-timer]

Finished benchmarking commit (3cad4c1): 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)	0.1%	[0.1%, 0.1%]	2
Improvements ✅ (primary)	-0.4%	[-0.5%, -0.3%]	5
Improvements ✅ (secondary)	-1.5%	[-18.4%, -0.0%]	22
All ❌✅ (primary)	-0.4%	[-0.5%, -0.3%]	5

Max RSS (memory usage)

Results (primary 0.9%, secondary 2.4%)

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

	mean	range	count
Regressions ❌ (primary)	2.5%	[2.4%, 2.5%]	2
Regressions ❌ (secondary)	4.5%	[2.3%, 5.1%]	8
Improvements ✅ (primary)	-0.6%	[-0.8%, -0.5%]	2
Improvements ✅ (secondary)	-1.9%	[-2.3%, -1.0%]	4
All ❌✅ (primary)	0.9%	[-0.8%, 2.5%]	4

Cycles

Results (primary 2.0%, secondary -1.9%)

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

	mean	range	count
Regressions ❌ (primary)	2.0%	[2.0%, 2.0%]	1
Regressions ❌ (secondary)	2.4%	[2.2%, 2.5%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.6%	[-5.5%, -2.2%]	5
All ❌✅ (primary)	2.0%	[2.0%, 2.0%]	1

Binary size

Results (secondary 0.0%)

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)	0.0%	[0.0%, 0.0%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Bootstrap: 471.273s -> 471.264s (-0.00%)
Artifact size: 387.92 MiB -> 389.96 MiB (0.53%)

[bors]

☔ The latest upstream changes (presumably #146879) made this pull request unmergeable. Please resolve the merge conflicts.