Redirect __rust_dealloc to sdallocx

[Zoxc]

This could use a perf run.

[rustbot]

r? @petrochenkov

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[Kobzol]

@bors try @rust-timer queue

[bors]

⌛ Trying commit 0f657ac with merge ecb3315...

[bors]

☀️ Try build successful - checks-actions
Build commit: ecb3315 (ecb331519998b3890fd9db9720e01106318d4103)

[rust-timer]

Finished benchmarking commit (ecb3315): 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 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)	-0.6%	[-1.2%, -0.2%]	148
Improvements ✅ (secondary)	-0.6%	[-3.8%, -0.3%]	80
All ❌✅ (primary)	-0.6%	[-1.2%, -0.2%]	148

Max RSS (memory usage)

Results

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)	3.2%	[2.2%, 4.6%]	8
Regressions ❌ (secondary)	3.5%	[1.8%, 5.0%]	27
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	3.2%	[2.2%, 4.6%]	8

Cycles

Results

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
Improvements ✅ (secondary)	-1.8%	[-1.9%, -1.7%]	2
All ❌✅ (primary)	-	-	0

Binary size

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

Bootstrap: 645.581s -> 646.145s (0.09%)
Artifact size: 309.97 MiB -> 309.93 MiB (-0.01%)

[Kobzol]

This was previously tried here, although seemingly in a different way. CC @nnethercote

[petrochenkov]

The PR needs a proper description - what exactly it changes and why it's different from jemalloc overrides below, why it helps, what __rust_dealloc and sdallocx are, etc.

[workingjubilee]

sdallocx is the jemalloc function that allows passing a size when deallocating, as an optimization, allowing the allocator to skip the relevant metadata lookup it would otherwise have to do.

[Zoxc]

If #122362 works out we could probably just do this change with a #[global_allocator].