Turn off speculative devirtualization by default. by meg-gupta · Pull Request #29359 · swiftlang/swift

meg-gupta · 2020-01-22T19:29:23Z

Also, add a flag to enable the pass.

Fixes rdar://58778959 and rdar://58429282

meg-gupta · 2020-01-22T19:30:00Z

\cc @airspeedswift

airspeedswift · 2020-01-22T19:31:12Z

Thanks!

airspeedswift · 2020-01-22T19:31:18Z

@swift-ci please benchmark

airspeedswift · 2020-01-22T19:31:23Z

@swift-ci please test

swift-ci · 2020-01-22T20:25:47Z

Performance: -O

Regression	OLD	NEW	DELTA	RATIO
SuffixAnySeqCntRangeLazy	445	38225	+8489.9%	0.01x
SuffixAnySeqCRangeIterLazy	491	38334	+7707.3%	0.01x
DropLastAnySeqCRangeIterLazy	576	38173	+6527.2%	0.02x
DropLastAnySeqCntRangeLazy	575	37945	+6499.1%	0.02x
SuffixAnySequenceLazy	1954	4244	+117.2%	0.46x
DropLastAnySequenceLazy	2039	3821	+87.4%	0.53x
CharacterLiteralsLarge	97	108	+11.3%	0.90x
ObjectiveCBridgeFromNSArrayAnyObjectToStringForced	43800	48600	+11.0%	0.90x (?)
RemoveWhereMoveInts	36	39	+8.3%	0.92x (?)
ObjectiveCBridgeStubNSDateRefAccess	371	400	+7.8%	0.93x (?)
EqualSubstringSubstring	39	42	+7.7%	0.93x
LessSubstringSubstring	39	42	+7.7%	0.93x
EqualSubstringSubstringGenericEquatable	39	42	+7.7%	0.93x
EqualSubstringString	39	42	+7.7%	0.93x (?)
LessSubstringSubstringGenericComparable	39	42	+7.7%	0.93x

Improvement	OLD	NEW	DELTA	RATIO
ObjectiveCBridgeStringHash	78	67	-14.1%	1.16x
FlattenListLoop	5321	4818	-9.5%	1.10x (?)
UTF8Decode_InitDecoding_ascii	288	263	-8.7%	1.10x (?)
NSStringConversion.MutableCopy.UTF8	883	816	-7.6%	1.08x (?)
Set.isDisjoint.Int.Empty	101	94	-6.9%	1.07x (?)
ObjectiveCBridgeStringGetASCIIContents	328	306	-6.7%	1.07x (?)

Code size: -O

Regression	OLD	NEW	DELTA	RATIO
PolymorphicCalls.o	7525	8101	+7.7%	0.93x

Improvement	OLD	NEW	DELTA	RATIO
DropLast.o	25065	22926	-8.5%	1.09x
Suffix.o	25298	23149	-8.5%	1.09x
Combos.o	5169	4974	-3.8%	1.04x
Hash.o	22990	22282	-3.1%	1.03x
Prefix.o	19794	19211	-2.9%	1.03x
DropFirst.o	20062	19506	-2.8%	1.03x
SequenceAlgos.o	19851	19463	-2.0%	1.02x
LuhnAlgoEager.o	10544	10353	-1.8%	1.02x
LuhnAlgoLazy.o	10544	10353	-1.8%	1.02x

Performance: -Osize

Regression	OLD	NEW	DELTA	RATIO
EqualSubstringSubstring	40	44	+10.0%	0.91x
EqualStringSubstring	40	44	+10.0%	0.91x (?)
EqualSubstringSubstringGenericEquatable	40	44	+10.0%	0.91x (?)
FlattenListFlatMap	7088	7699	+8.6%	0.92x (?)
EqualSubstringString	39	42	+7.7%	0.93x (?)

Improvement	OLD	NEW	DELTA	RATIO
ObjectiveCBridgeStringHash	78	67	-14.1%	1.16x
ObjectiveCBridgeStringCStringUsingEncoding	575	534	-7.1%	1.08x (?)
NSStringConversion.MutableCopy.Rebridge.UTF8	742	692	-6.7%	1.07x (?)
ObjectiveCBridgeStringGetASCIIContents	328	306	-6.7%	1.07x (?)

Code size: -Osize

Performance: -Onone

Regression	OLD	NEW	DELTA	RATIO
ClassArrayGetter2	3940	4350	+10.4%	0.91x

Improvement	OLD	NEW	DELTA	RATIO
ObjectiveCBridgeStringHash	78	67	-14.1%	1.16x
Set.subtracting.Seq.Int100	8065	7376	-8.5%	1.09x (?)
DataToStringMedium	5950	5450	-8.4%	1.09x (?)

Code size: -swiftlibs

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

swift-ci · 2020-01-22T20:32:51Z

Build failed
Swift Test OS X Platform
Git Sha - 3cd8f5de4fedd27ec4fb684012a702b0b1c7f049

swift-ci · 2020-01-22T20:33:11Z

Build failed
Swift Test Linux Platform
Git Sha - 3cd8f5de4fedd27ec4fb684012a702b0b1c7f049

meg-gupta · 2020-01-23T02:47:14Z

@swift-ci please test

swift-ci · 2020-01-23T02:49:43Z

Build failed
Swift Test Linux Platform
Git Sha - 3cd8f5de4fedd27ec4fb684012a702b0b1c7f049

swift-ci · 2020-01-23T02:50:40Z

Build failed
Swift Test OS X Platform
Git Sha - 3cd8f5de4fedd27ec4fb684012a702b0b1c7f049

meg-gupta · 2020-01-23T06:36:03Z

@swift-ci please test

swift-ci · 2020-01-23T06:38:18Z

Build failed
Swift Test Linux Platform
Git Sha - f7a8a8e58ea23777947c1b21fc071071a8e8a098

swift-ci · 2020-01-23T06:39:40Z

Build failed
Swift Test OS X Platform
Git Sha - f7a8a8e58ea23777947c1b21fc071071a8e8a098

eeckstein

lgtm!

meg-gupta · 2020-01-23T20:37:36Z

@swift-ci please test

swift-ci · 2020-01-23T20:38:23Z

Build failed
Swift Test OS X Platform
Git Sha - 510bcd487fa627871cb9813183e32d63b87b6aa9

swift-ci · 2020-01-23T20:40:27Z

Build failed
Swift Test Linux Platform
Git Sha - 510bcd487fa627871cb9813183e32d63b87b6aa9

…rt enabling the pass. Fixes rdar://58778959 and rdar://58429282

meg-gupta · 2020-01-24T08:53:20Z

@swift-ci please smoke test

This is a cherrypick of swiftlang#29359 Explanation: Disable speculative devirtualization optimization. The optimization did not give significant performance wins. Disabling it improves code size. Risk: Low. No significant performance hit is expected. Issue: rdar://problem/58778959 Testing: Performance tests and regression tests Reviewer: Erik Eckstein

This is a cherrypick of #29359 Explanation: Disable speculative devirtualization optimization. The optimization did not give significant performance wins. Disabling it improves code size. Risk: Low. No significant performance hit is expected. Issue: rdar://problem/58778959 Testing: Performance tests and regression tests Reviewer: Erik Eckstein

meg-gupta force-pushed the disablespecdevirt branch from f7a8a8e to 510bcd4 Compare January 23, 2020 06:34

eeckstein approved these changes Jan 23, 2020

View reviewed changes

meg-gupta added 3 commits January 23, 2020 14:24

Turn off speculative devirtualization by default. Add a flag to suppo…

9d79853

…rt enabling the pass. Fixes rdar://58778959 and rdar://58429282

Add check in sil-opt, add flags to tests

c55e57b

Fix more tests failing in release build

4e4981a

meg-gupta force-pushed the disablespecdevirt branch from eaaf641 to 4e4981a Compare January 23, 2020 23:55

meg-gupta merged commit 5285bf7 into swiftlang:master Jan 24, 2020

meg-gupta mentioned this pull request Jan 28, 2020

[5.2] Turn off speculative devirtualization by default. #29514

Merged

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meg-gupta commented Jan 22, 2020

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airspeedswift commented Jan 22, 2020

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swift-ci commented Jan 22, 2020

Performance: -O

Code size: -O

Performance: -Osize

Code size: -Osize

Performance: -Onone

Code size: -swiftlibs

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