[stdlib] Mark _NativeDictionary._delete(at:) non-releasing

[lorentey]

This eliminates a retain/release pair around calls to it when it doesn’t get inlined.

_delete is responsible for restoring hash table invariants after a removal. It moves elements around in complicated patterns, but it doesn’t release them.

[lorentey]

@swift-ci please smoke benchmark

[lorentey]

@swift-ci please test

[swift-ci]

Build comment file:

Performance: -O

TEST	OLD	NEW	DELTA	RATIO
Regression
CStringLongAscii	3289	3538	+7.6%	0.93x
Improvement
DictionaryRemove	6241	4337	-30.5%	1.44x

Performance: -Osize

TEST	OLD	NEW	DELTA	RATIO
Improvement
DictionaryRemove	8500	7677	-9.7%	1.11x

Performance: -Onone

TEST	OLD	NEW	DELTA	RATIO
Regression
CStringLongAscii	3388	3644	+7.6%	0.93x
Improvement
ArrayOfPOD	859	781	-9.1%	1.10x (?)

How to read the data

The tables contain differences in performance which are larger than 8% and differences in code size which are larger than 1%.

If you see any unexpected regressions, you should consider fixing the regressions before you merge the PR.

Noise: Sometimes the performance results (not code size!) contain false alarms. Unexpected regressions which are marked with '(?)' are probably noise. If you see regressions which you cannot explain you can try to run the benchmarks again. If regressions still show up, please consult with the performance team (@eeckstein).

Hardware Overview

  Model Name: Mac Pro
  Model Identifier: MacPro6,1
  Processor Name: 12-Core Intel Xeon E5
  Processor Speed: 2.7 GHz
  Number of Processors: 1
  Total Number of Cores: 12
  L2 Cache (per Core): 256 KB
  L3 Cache: 30 MB
  Memory: 64 GB

---

[lorentey]

cc @airspeedswift

[lorentey]

Set should be invited to this party, too.

@swift-ci smoke benchmark

[lorentey]

@swift-ci please test

[swift-ci]

Build comment file:

Performance: -O

TEST	OLD	NEW	DELTA	RATIO
Regression
CStringLongAscii	3289	3538	+7.6%	0.93x
Improvement
DictionaryRemove	6331	4443	-29.8%	1.42x
DictionaryRemoveOfObjects	22565	20974	-7.1%	1.08x

Performance: -Osize

TEST	OLD	NEW	DELTA	RATIO
Improvement
DictionaryRemove	8872	7975	-10.1%	1.11x

Performance: -Onone

TEST	OLD	NEW	DELTA	RATIO
Regression
CStringLongAscii	3391	3674	+8.3%	0.92x
Improvement
ArrayOfPOD	858	781	-9.0%	1.10x (?)

How to read the data

The tables contain differences in performance which are larger than 8% and differences in code size which are larger than 1%.

If you see any unexpected regressions, you should consider fixing the regressions before you merge the PR.

Noise: Sometimes the performance results (not code size!) contain false alarms. Unexpected regressions which are marked with '(?)' are probably noise. If you see regressions which you cannot explain you can try to run the benchmarks again. If regressions still show up, please consult with the performance team (@eeckstein).

Hardware Overview

  Model Name: Mac Pro
  Model Identifier: MacPro6,1
  Processor Name: 12-Core Intel Xeon E5
  Processor Speed: 2.7 GHz
  Number of Processors: 1
  Total Number of Cores: 12
  L2 Cache (per Core): 256 KB
  L3 Cache: 30 MB
  Memory: 64 GB

---