Cfg trace attributes, attempt 2

[JonathanBrouwer]

Proof of concept, the code is veeeryyy ugly

[JonathanBrouwer]

@bors try @rust-timer queue

[rust-bors]

☀️ Try build successful (CI)
Build commit: ed1fb29 (ed1fb2931c0b2ef01da69d775ed80af9ece506fe, parent: 0bd13c38df9a9a922bd8ec98ba7a8bc7e111860e)

[rust-timer]

Finished benchmarking commit (ed1fb29): comparison URL.

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

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.

Next Steps: If you can justify the regressions found in this try perf run, please do so in sufficient writing along with @rustbot label: +perf-regression-triaged. If not, please fix the regressions and do another perf run. If its results are neutral or positive, the label will be automatically removed.

@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)	0.3%	[0.2%, 0.7%]	6
Regressions ❌ (secondary)	0.3%	[0.1%, 0.8%]	5
Improvements ✅ (primary)	-0.3%	[-0.5%, -0.1%]	15
Improvements ✅ (secondary)	-0.1%	[-0.2%, -0.0%]	15
All ❌✅ (primary)	-0.1%	[-0.5%, 0.7%]	21

Max RSS (memory usage)

Results (primary -0.9%, 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)	0.8%	[0.8%, 0.8%]	1
Regressions ❌ (secondary)	1.3%	[1.2%, 1.3%]	2
Improvements ✅ (primary)	-1.4%	[-2.4%, -0.9%]	3
Improvements ✅ (secondary)	-1.0%	[-1.2%, -0.8%]	3
All ❌✅ (primary)	-0.9%	[-2.4%, 0.8%]	4

Cycles

Results (primary 2.8%, secondary 10.9%)

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

	mean	range	count
Regressions ❌ (primary)	2.8%	[2.3%, 3.3%]	2
Regressions ❌ (secondary)	10.9%	[2.1%, 26.6%]	19
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	2.8%	[2.3%, 3.3%]	2

Binary size

Results (primary -0.4%, secondary -0.2%)

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)	-0.4%	[-1.9%, -0.0%]	78
Improvements ✅ (secondary)	-0.2%	[-0.9%, -0.0%]	16
All ❌✅ (primary)	-0.4%	[-1.9%, -0.0%]	78

Bootstrap: 481.073s -> 480.532s (-0.11%)
Artifact size: 390.31 MiB -> 390.37 MiB (0.02%)