bootstrap: build std sans leaf frame pointers

[workingjubilee]

Sometimes leaf frame-pointers can impact LLVM inlining choices, and that can be a real problem for things like mul_add.

[workingjubilee]

@bors2 try @rust-timer queue

[rust-bors]

⌛ Trying commit 2d5d55a with merge 53f6b1b…

[rust-bors]

☀️ Try build successful

• CI ✅
  Build commit: 53f6b1b (53f6b1bd2116ea8d2f8cbd88780fa56984c18c0e)

[rust-timer]

Finished benchmarking commit (53f6b1b): 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
Improvements ✅ (secondary)	-0.3%	[-0.4%, -0.2%]	3
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (secondary -0.4%)

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)	0.5%	[0.5%, 0.5%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.7%	[-0.9%, -0.4%]	7
All ❌✅ (primary)	-	-	0

Cycles

Results (secondary -0.6%)

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)	-	-	0
Regressions ❌ (secondary)	1.0%	[0.7%, 1.2%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-0.8%	[-2.4%, -0.4%]	13
All ❌✅ (primary)	-	-	0

Binary size

Results (primary -0.3%, secondary -0.6%)

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)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.3%	[-0.6%, -0.1%]	11
Improvements ✅ (secondary)	-0.6%	[-0.6%, -0.4%]	38
All ❌✅ (primary)	-0.3%	[-0.6%, -0.1%]	11

Bootstrap: 778.921s -> 776.952s (-0.25%)
Artifact size: 370.25 MiB -> 370.14 MiB (-0.03%)

[workingjubilee]

Performance is almost completely invisible on a large, noisy program like rustc. But the improvements are more notable in binary size where they are modest but consistent. Not sure how to interpret the wall-time regressions in large-workspace, though.

[saethlin]

Not sure how to interpret the wall-time regressions in large-workspace, though.

Get a new commit hash and try again. It's probably instability.

[saethlin]

Oh. Most of the large-workspace significance thresholds are still the default 0.20%. The significance estimations just aren't calibrated yet.

[workingjubilee]

I'm gonna assume that means I shouldn't worry too much about it.

r? compiler

[saethlin]

Yeah, there's just no information to be gleaned from that benchmark. Yet.

I don't know what the right reviewer group is for "how we build the precompiled sysroot" but I've been involved in this discussion a fair bit and support this change.

r? saethlin
@bors r+

[bors]

📌 Commit 2d5d55a has been approved by saethlin

It is now in the queue for this repository.