[perf] Enable inlining trait items that only contain inlined code.

[obi1kenobi]

TODO: Fill in if shown to improve perf.

r? oli-obk

[Kobzol]

@bors try @rust-timer queue

[rust-bors]

☀️ Try build successful (CI)
Build commit: 20bd965 (20bd9651565dfb3135d6e60029dfd8f975ff5329)
Base parent: 48e8ec6 (48e8ec6f05057f942a97187dde770a118e05f42c)

[rust-timer]

Finished benchmarking commit (20bd965): comparison URL.

Overall result: ❌✅ regressions and improvements - please read:

Benchmarking means the PR may be perf-sensitive. It's automatically marked not fit for rolling up. Overriding is possible but disadvised: it risks changing compiler perf.

Next, please: If you can, justify the regressions found in this try perf run in writing along with @rustbot label: +perf-regression-triaged. If not, fix the regressions and do another perf run. Neutral or positive results will clear the label automatically.

@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%	[0.2%, 1.7%]	17
Regressions ❌ (secondary)	0.4%	[0.0%, 0.7%]	29
Improvements ✅ (primary)	-1.7%	[-6.3%, -0.3%]	5
Improvements ✅ (secondary)	-0.3%	[-4.3%, -0.0%]	31
All ❌✅ (primary)	-0.0%	[-6.3%, 1.7%]	22

Max RSS (memory usage)

Results (primary 0.9%, secondary 1.1%)

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

	mean	range	count
Regressions ❌ (primary)	3.0%	[2.7%, 3.3%]	2
Regressions ❌ (secondary)	3.1%	[3.1%, 3.1%]	1
Improvements ✅ (primary)	-3.2%	[-3.2%, -3.2%]	1
Improvements ✅ (secondary)	-0.9%	[-0.9%, -0.9%]	1
All ❌✅ (primary)	0.9%	[-3.2%, 3.3%]	3

Cycles

Results (primary -7.0%, secondary 5.4%)

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)	10.1%	[1.8%, 19.7%]	11
Improvements ✅ (primary)	-7.0%	[-7.0%, -7.0%]	1
Improvements ✅ (secondary)	-3.3%	[-5.4%, -2.0%]	6
All ❌✅ (primary)	-7.0%	[-7.0%, -7.0%]	1

Binary size

Results (primary -0.0%, secondary 0.1%)

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

	mean	range	count
Regressions ❌ (primary)	0.5%	[0.1%, 0.7%]	4
Regressions ❌ (secondary)	0.3%	[0.1%, 0.4%]	2
Improvements ✅ (primary)	-0.3%	[-1.5%, -0.0%]	9
Improvements ✅ (secondary)	-0.3%	[-0.3%, -0.3%]	1
All ❌✅ (primary)	-0.0%	[-1.5%, 0.7%]	13

Bootstrap: 490.729s -> 491.057s (0.07%)
Artifact size: 389.29 MiB -> 389.83 MiB (0.14%)

[Kobzol]

Looks like this does indeed help specifically nom-json a lot (https://perf.rust-lang.org/compare.html?start=48e8ec6f05057f942a97187dde770a118e05f42c&end=20bd9651565dfb3135d6e60029dfd8f975ff5329&stat=instructions%3Au&tab=runtime).