[4.0] String performance optimizations #10223

dabrahams · 2017-06-13T18:48:32Z

Explanation: String optimizations
Scope: optimizations
Radar: rdar://32744663 String Optimizations for Swift 4 beta 3
Risk: very low
Testing: Passed full validation + benchmarking on master; validation and source compatibility on the 4.0 branch (benchmark testing on 4.0 branch not supported)

This is a way of testing infrastructure for an updated UTF8View iterator

dabrahams · 2017-06-13T18:48:49Z

@swift-ci Please test

dabrahams · 2017-06-13T18:49:04Z

@swift-ci Please test source compatibility

dabrahams · 2017-06-13T18:49:22Z

@swift-ci Please benchmark

moiseev · 2017-06-13T21:00:24Z

stdlib/public/core/ValidUTF8Buffer.swift

+  }
+}
+
+/*


Looks like a development process artifact. Should it be removed?

Good catch. Yes, it should be removed, though since it's benign I'd rather do this in master as a separate thing and let it land in a release later.

moiseev

swift-ci · 2017-06-13T21:19:45Z

Build comment file:

Build failed before running benchmark.

dabrahams · 2017-06-13T22:45:07Z

@shahmishal I don't understand the failure. Should we just run the benchmark again?

shahmishal · 2017-06-13T22:59:18Z

Benchmark driver is written to only work with master branch

https://github.com/apple/swift/blob/swift-4.0-branch/benchmark/scripts/Benchmark_Driver#L292

if current_branch != 'master' and not os.path.isdir(master_branch_dir):
        print('Unable to find benchmark logs for master branch. Set a ' +
              'baseline benchmark log by passing --benchmark to ' +
              'build-script while on master branch.')
        return 1

dabrahams · 2017-06-14T15:07:58Z

Locally-derived benchmark results (-O):

Regression (10)

TEST	OLD	NEW	DELTA	SPEEDUP
ObserverForwarderStruct	971	1191	+22.7%	0.82x
ProtocolDispatch	2153	2626	+22.0%	0.82x
StringBuilderLong	804	941	+17.0%	0.85x
MonteCarloE	8874	9866	+11.2%	0.90x
ObjectiveCBridgeStubDateAccess	188	209	+11.2%	0.90x
Memset	178	195	+9.6%	0.91x
Array2D	1684	1839	+9.2%	0.92x
Calculator	29	31	+6.9%	0.94x
MapReduceString	90	96	+6.7%	0.94x
DropWhileAnyCollectionLazy	92	98	+6.5%	0.94x

Improvement (57)

TEST	OLD	NEW	DELTA	SPEEDUP
Chars	1835	732	-60.1%	2.51x
SuffixArrayLazy	10	6	-40.0%	1.67x
SuffixArray	10	6	-40.0%	1.67x
SuperChars	163185	130367	-20.1%	1.25x
DropWhileCountableRange	25	20	-20.0%	1.25x
StringWalk	1108	889	-19.8%	1.25x
StrComplexWalk	737	608	-17.5%	1.21x
LazilyFilteredArrays	56308	46857	-16.8%	1.20x
PrefixSequenceLazy	1637	1386	-15.3%	1.18x
ObjectiveCBridgeFromNSStringForced	2075	1817	-12.4%	1.14x
OpenClose	50	44	-12.0%	1.14x
SuffixSequenceLazy	4411	3883	-12.0%	1.14x
ObjectiveCBridgeStubFromArrayOfNSString	25506	22570	-11.5%	1.13x
SuffixCountableRangeLazy	9	8	-11.1%	1.12x
SuffixCountableRange	9	8	-11.1%	1.12x
DropLastCountableRangeLazy	9	8	-11.1%	1.12x
ObjectiveCBridgeFromNSSetAnyObjectToStringForced	57533	51447	-10.6%	1.12x
PrefixWhileSequenceLazy	29	26	-10.3%	1.12x
StringWithCString	55048	49505	-10.1%	1.11x
PolymorphicCalls	20	18	-10.0%	1.11x
PrefixSequence	1569	1417	-9.7%	1.11x
NSDictionaryCastToSwift	4937	4489	-9.1%	1.10x
ObjectAllocation	171	157	-8.2%	1.09x
CharacterLiteralsSmall	315	290	-7.9%	1.09x
ObjectiveCBridgeToNSArray	25782	23777	-7.8%	1.08x
BitCount	13	12	-7.7%	1.08x
DropLastSequenceLazy	446	412	-7.6%	1.08x
Walsh	299	277	-7.4%	1.08x
SubstringEqualString	3103	2878	-7.3%	1.08x
SetExclusiveOr	2689	2495	-7.2%	1.08x
PrefixWhileAnySeqCRangeIterLazy	70	65	-7.1%	1.08x
PrefixWhileCountableRangeLazy	28	26	-7.1%	1.08x
ObjectiveCBridgeFromNSDictionaryAnyObjectForced	4707	4383	-6.9%	1.07x
ArrayOfPOD	146	136	-6.8%	1.07x
SuffixAnySeqCntRange	15	14	-6.7%	1.07x
DropLastSequence	441	412	-6.6%	1.07x
ObjectiveCBridgeFromNSArrayAnyObjectForced	3937	3686	-6.4%	1.07x
PrefixWhileAnySeqCRangeIter	11715	10977	-6.3%	1.07x
ReversedArray	48	45	-6.2%	1.07x
StringHasPrefix	16	15	-6.2%	1.07x
NopDeinit	24934	23442	-6.0%	1.06x
ObjectiveCBridgeFromNSArrayAnyObjectToStringForced	32537	30596	-6.0%	1.06x
MapReduce	253	238	-5.9%	1.06x
StaticArray	17	16	-5.9%	1.06x
SortStringsUnicode	19333	18238	-5.7%	1.06x
SubstringEquatable	6608	6235	-5.6%	1.06x
PrefixWhileArray	55	52	-5.5%	1.06x
SortSortedStrings	779	739	-5.1%	1.05x
ObjectiveCBridgeStubDataAppend	3588	3404	-5.1%	1.05x
DropWhileSequenceLazy	59	56	-5.1%	1.05x
SevenBoom	1325	1258	-5.1%	1.05x
SuffixAnyCollection	20	19	-5.0%	1.05x
DropFirstArray	20	19	-5.0%	1.05x
DropLastAnyCollection	20	19	-5.0%	1.05x
DropFirstArrayLazy	20	19	-5.0%	1.05x
StringFromLongWholeSubstringGeneric	20	19	-5.0%	1.05x
ObjectiveCBridgeFromNSDictionaryAnyObjectToStringForced	81209	77173	-5.0%	1.05x

No Changes (214)

TEST	OLD	NEW	DELTA	SPEEDUP
AngryPhonebook	2593	2706	+4.4%	0.96x
AnyHashableWithAClass	58659	59777	+1.9%	0.98x
ArrayAppend	495	489	-1.2%	1.01x
ArrayAppendArrayOfInt	357	366	+2.5%	0.98x
ArrayAppendAscii	17795	17789	-0.0%	1.00x
ArrayAppendFromGeneric	348	352	+1.1%	0.99x
ArrayAppendGenericStructs	723	701	-3.0%	1.03x
ArrayAppendLatin1	32570	32020	-1.7%	1.02x
ArrayAppendLazyMap	716	715	-0.1%	1.00x
ArrayAppendOptionals	702	695	-1.0%	1.01x
ArrayAppendRepeatCol	622	621	-0.2%	1.00x
ArrayAppendReserved	334	334	+0.0%	1.00x
ArrayAppendSequence	675	682	+1.0%	0.99x
ArrayAppendStrings	13674	13583	-0.7%	1.01x
ArrayAppendToFromGeneric	351	355	+1.1%	0.99x
ArrayAppendToGeneric	348	356	+2.3%	0.98x
ArrayAppendUTF16	30538	30588	+0.2%	1.00x
ArrayInClass	54	55	+1.9%	0.98x
ArrayLiteral	1069	1075	+0.6%	0.99x
ArrayOfGenericPOD	191	188	-1.6%	1.02x
ArrayOfGenericRef	3539	3603	+1.8%	0.98x
ArrayOfRef	3731	3592	-3.7%	1.04x
ArrayPlusEqualArrayOfInt	352	355	+0.9%	0.99x
ArrayPlusEqualFiveElementCollection	3731	3617	-3.1%	1.03x
ArrayPlusEqualSingleElementCollection	482	493	+2.3%	0.98x
ArrayPlusEqualThreeElements	1395	1386	-0.6%	1.01x
ArraySubscript	1309	1334	+1.9%	0.98x
ArrayValueProp	5	5	+0.0%	1.00x
ArrayValueProp2	5	5	+0.0%	1.00x
ArrayValueProp3	5	5	+0.0%	1.00x
ArrayValueProp4	5	5	+0.0%	1.00x
ByteSwap	0	0	+0.0%	1.00x
CStringLongAscii	4003	4101	+2.4%	0.98x
CStringLongNonAscii	1689	1750	+3.6%	0.97x
CStringShortAscii	4867	4760	-2.2%	1.02x
CaptureProp	4020	4115	+2.4%	0.98x
CharacterLiteralsLarge	4950	5098	+3.0%	0.97x
ClassArrayGetter	11	11	+0.0%	1.00x
DeadArray	132	130	-1.5%	1.02x
Dictionary	469	451	-3.8%	1.04x
Dictionary2	1549	1534	-1.0%	1.01x
Dictionary2OfObjects	2833	2803	-1.1%	1.01x
Dictionary3	411	405	-1.5%	1.01x
Dictionary3OfObjects	787	774	-1.7%	1.02x
DictionaryBridge	2702	2587	-4.3%	1.04x
DictionaryLiteral	1265	1253	-0.9%	1.01x
DictionaryOfObjects	2052	1977	-3.7%	1.04x
DictionaryRemove	2013	1934	-3.9%	1.04x
DictionaryRemoveOfObjects	20156	20100	-0.3%	1.00x
DictionarySwap	329	328	-0.3%	1.00x
DictionarySwapOfObjects	6037	5992	-0.7%	1.01x
DropFirstAnyCollection	51	50	-2.0%	1.02x
DropFirstAnyCollectionLazy	41276	40387	-2.2%	1.02x
DropFirstAnySeqCRangeIter	23838	23809	-0.1%	1.00x
DropFirstAnySeqCRangeIterLazy	23776	23981	+0.9%	0.99x
DropFirstAnySeqCntRange	45	43	-4.4%	1.05x
DropFirstAnySeqCntRangeLazy	44	43	-2.3%	1.02x
DropFirstAnySequence	5120	5068	-1.0%	1.01x
DropFirstAnySequenceLazy	5093	5054	-0.8%	1.01x
DropFirstCountableRange	27	26	-3.7%	1.04x
DropFirstCountableRangeLazy	26	26	+0.0%	1.00x
DropFirstSequence	1914	1887	-1.4%	1.01x
DropFirstSequenceLazy	1907	1831	-4.0%	1.04x
DropLastAnyCollectionLazy	14007	13541	-3.3%	1.03x
DropLastAnySeqCRangeIter	4143	4079	-1.5%	1.02x
DropLastAnySeqCRangeIterLazy	4153	4117	-0.9%	1.01x
DropLastAnySeqCntRange	14	14	+0.0%	1.00x
DropLastAnySeqCntRangeLazy	14	14	+0.0%	1.00x
DropLastAnySequence	5976	5845	-2.2%	1.02x
DropLastAnySequenceLazy	5924	5816	-1.8%	1.02x
DropLastArray	6	6	+0.0%	1.00x
DropLastArrayLazy	6	6	+0.0%	1.00x
DropLastCountableRange	8	8	+0.0%	1.00x
DropWhileAnyCollection	63	60	-4.8%	1.05x
DropWhileAnySeqCRangeIter	19284	18567	-3.7%	1.04x
DropWhileAnySeqCRangeIterLazy	91	90	-1.1%	1.01x
DropWhileAnySeqCntRange	57	55	-3.5%	1.04x
DropWhileAnySeqCntRangeLazy	92	90	-2.2%	1.02x
DropWhileAnySequence	5832	5722	-1.9%	1.02x
DropWhileAnySequenceLazy	1872	1838	-1.8%	1.02x
DropWhileArray	31	32	+3.2%	0.97x
DropWhileArrayLazy	68	70	+2.9%	0.97x
DropWhileCountableRangeLazy	60	59	-1.7%	1.02x
DropWhileSequence	1426	1400	-1.8%	1.02x
EqualStringSubstring	421	427	+1.4%	0.99x
EqualSubstringString	411	405	-1.5%	1.01x
EqualSubstringSubstring	416	404	-2.9%	1.03x
EqualSubstringSubstringGenericEquatable	414	404	-2.4%	1.02x
ErrorHandling	2460	2393	-2.7%	1.03x
GlobalClass	0	0	+0.0%	1.00x
Hanoi	3017	3049	+1.1%	0.99x
HashTest	1394	1438	+3.2%	0.97x
Histogram	233	227	-2.6%	1.03x
Integrate	208	202	-2.9%	1.03x
IterateData	638	616	-3.4%	1.04x
Join	340	325	-4.4%	1.05x
LazilyFilteredRange	2867	2799	-2.4%	1.02x
LessSubstringSubstring	408	408	+0.0%	1.00x
LessSubstringSubstringGenericComparable	420	400	-4.8%	1.05x
LinkedList	6329	6238	-1.4%	1.01x
MapReduceAnyCollection	254	242	-4.7%	1.05x
MapReduceAnyCollectionShort	1777	1731	-2.6%	1.03x
MapReduceClass	2709	2646	-2.3%	1.02x
MapReduceClassShort	4041	3902	-3.4%	1.04x
MapReduceLazyCollection	14	14	+0.0%	1.00x
MapReduceLazyCollectionShort	37	38	+2.7%	0.97x
MapReduceLazySequence	79	81	+2.5%	0.98x
MapReduceSequence	401	406	+1.2%	0.99x
MapReduceShort	1729	1692	-2.1%	1.02x
MapReduceShortString	19	19	+0.0%	1.00x
MonteCarloPi	38569	37610	-2.5%	1.03x
NSError	267	256	-4.1%	1.04x
NSStringConversion	602	595	-1.2%	1.01x
ObjectiveCBridgeFromNSArrayAnyObject	20220	20098	-0.6%	1.01x
ObjectiveCBridgeFromNSArrayAnyObjectToString	37211	36435	-2.1%	1.02x
ObjectiveCBridgeFromNSDictionaryAnyObject	102451	101435	-1.0%	1.01x
ObjectiveCBridgeFromNSDictionaryAnyObjectToString	88508	85787	-3.1%	1.03x
ObjectiveCBridgeFromNSSetAnyObject	54865	56480	+2.9%	0.97x
ObjectiveCBridgeFromNSSetAnyObjectForced	3398	3476	+2.3%	0.98x
ObjectiveCBridgeFromNSSetAnyObjectToString	62533	59773	-4.4%	1.05x
ObjectiveCBridgeFromNSString	1305	1272	-2.5%	1.03x
ObjectiveCBridgeStubDateMutation	243	235	-3.3%	1.03x
ObjectiveCBridgeStubFromNSDate	2945	2829	-3.9%	1.04x
ObjectiveCBridgeStubFromNSDateRef	3078	2988	-2.9%	1.03x
ObjectiveCBridgeStubFromNSString	743	711	-4.3%	1.05x
ObjectiveCBridgeStubFromNSStringRef	137	131	-4.4%	1.05x
ObjectiveCBridgeStubNSDataAppend	2143	2099	-2.1%	1.02x
ObjectiveCBridgeStubNSDateMutationRef	10667	10951	+2.7%	0.97x
ObjectiveCBridgeStubNSDateRefAccess	278	268	-3.6%	1.04x
ObjectiveCBridgeStubToArrayOfNSString	25020	24772	-1.0%	1.01x
ObjectiveCBridgeStubToNSDate	13323	13239	-0.6%	1.01x
ObjectiveCBridgeStubToNSDateRef	2894	2806	-3.0%	1.03x
ObjectiveCBridgeStubToNSString	1304	1272	-2.5%	1.03x
ObjectiveCBridgeStubToNSStringRef	89	87	-2.2%	1.02x
ObjectiveCBridgeStubURLAppendPath	195649	187135	-4.4%	1.05x
ObjectiveCBridgeStubURLAppendPathRef	198534	189804	-4.4%	1.05x
ObjectiveCBridgeToNSDictionary	42235	40835	-3.3%	1.03x
ObjectiveCBridgeToNSSet	36282	35328	-2.6%	1.03x
ObjectiveCBridgeToNSString	1089	1059	-2.8%	1.03x
ObserverClosure	1982	1961	-1.1%	1.01x
ObserverPartiallyAppliedMethod	3391	3287	-3.1%	1.03x
ObserverUnappliedMethod	2296	2204	-4.0%	1.04x
Phonebook	5280	5301	+0.4%	1.00x
PopFrontArray	898	893	-0.6%	1.01x
PopFrontArrayGeneric	878	868	-1.1%	1.01x
PopFrontUnsafePointer	7689	7521	-2.2%	1.02x
PrefixAnyCollection	51	49	-3.9%	1.04x
PrefixAnyCollectionLazy	40841	39979	-2.1%	1.02x
PrefixAnySeqCRangeIter	18582	18276	-1.6%	1.02x
PrefixAnySeqCRangeIterLazy	18803	18278	-2.8%	1.03x
PrefixAnySeqCntRange	45	43	-4.4%	1.05x
PrefixAnySeqCntRangeLazy	45	44	-2.2%	1.02x
PrefixAnySequence	4541	4367	-3.8%	1.04x
PrefixAnySequenceLazy	4472	4383	-2.0%	1.02x
PrefixArray	19	19	+0.0%	1.00x
PrefixArrayLazy	19	19	+0.0%	1.00x
PrefixCountableRange	27	26	-3.7%	1.04x
PrefixCountableRangeLazy	27	26	-3.7%	1.04x
PrefixWhileAnyCollection	87	84	-3.4%	1.04x
PrefixWhileAnyCollectionLazy	68	66	-2.9%	1.03x
PrefixWhileAnySeqCntRange	79	77	-2.5%	1.03x
PrefixWhileAnySeqCntRangeLazy	68	65	-4.4%	1.05x
PrefixWhileAnySequence	12604	12361	-1.9%	1.02x
PrefixWhileAnySequenceLazy	1434	1368	-4.6%	1.05x
PrefixWhileArrayLazy	43	42	-2.3%	1.02x
PrefixWhileCountableRange	23	22	-4.3%	1.05x
PrefixWhileSequence	234	232	-0.9%	1.01x
Prims	675	646	-4.3%	1.04x
ProtocolDispatch2	150	149	-0.7%	1.01x
RC4	102	98	-3.9%	1.04x
RGBHistogram	1950	1883	-3.4%	1.04x
RGBHistogramOfObjects	21849	21124	-3.3%	1.03x
RangeAssignment	254	254	+0.0%	1.00x
RecursiveOwnedParameter	1785	1739	-2.6%	1.03x
ReversedBidirectional	26365	25390	-3.7%	1.04x
ReversedDictionary	130	134	+3.1%	0.97x
SetExclusiveOr_OfObjects	8260	8140	-1.5%	1.01x
SetIntersect	222	212	-4.5%	1.05x
SetIntersect_OfObjects	1521	1479	-2.8%	1.03x
SetIsSubsetOf	273	265	-2.9%	1.03x
SetIsSubsetOf_OfObjects	348	338	-2.9%	1.03x
SetUnion	2314	2274	-1.7%	1.02x
SetUnion_OfObjects	6800	6666	-2.0%	1.02x
Sim2DArray	236	228	-3.4%	1.04x
SortLargeExistentials	6737	6639	-1.5%	1.01x
SortLettersInPlace	1005	993	-1.2%	1.01x
SortStrings	1451	1434	-1.2%	1.01x
StackPromo	20166	19641	-2.6%	1.03x
StrToInt	1761	1699	-3.5%	1.04x
StringAdder	0	0	+0.0%	1.00x
StringBuilder	826	859	+4.0%	0.96x
StringEdits	88811	87510	-1.5%	1.01x
StringEqualPointerComparison	245	236	-3.7%	1.04x
StringFromLongWholeSubstring	8459	8276	-2.2%	1.02x
StringHasPrefixUnicode	34216	32820	-4.1%	1.04x
StringHasSuffix	16	16	+0.0%	1.00x
StringHasSuffixUnicode	72395	70730	-2.3%	1.02x
StringInterpolation	8994	9128	+1.5%	0.99x
StringMatch	6010	5883	-2.1%	1.02x
StringUTF16Builder	1555	1587	+2.1%	0.98x
SubstringComparable	3185	3160	-0.8%	1.01x
SubstringFromLongString	85	82	-3.5%	1.04x
SubstringFromLongStringGeneric	148	154	+4.1%	0.96x
SuffixAnyCollectionLazy	13742	13351	-2.8%	1.03x
SuffixAnySeqCRangeIter	4518	4358	-3.5%	1.04x
SuffixAnySeqCRangeIterLazy	4499	4334	-3.7%	1.04x
SuffixAnySeqCntRangeLazy	14	14	+0.0%	1.00x
SuffixAnySequence	6053	6010	-0.7%	1.01x
SuffixAnySequenceLazy	6130	6070	-1.0%	1.01x
SuffixSequence	4004	3875	-3.2%	1.03x
TwoSum	828	815	-1.6%	1.02x
TypeFlood	0	0	+0.0%	1.00x
UTF8Decode	214	204	-4.7%	1.05x
XorLoop	256	264	+3.1%	0.97x

Dave Abrahams added 6 commits June 13, 2017 11:33

[stdlib] Access a Character's .unicodeScalars without allocation

cf337f8

[stdlib] Inline Character comparison fast paths

8dd4341

[stdlib] Replace UTF8.EncodedScalar

ad0f02a

This is a way of testing infrastructure for an updated UTF8View iterator

[stdlib] Rewrite UTF16.transcodedLength

4f0a463

[stdlib] ASCII fastpath for UTF16.transcodedLength

9aff0ec

[stdlib] Inline fast paths of String append

508008b

airspeedswift changed the title ~~String Optimizations for Swift 4 beta 3~~ [4.0] String performance optimizations Jun 13, 2017

dabrahams requested review from milseman and moiseev June 13, 2017 20:30

moiseev reviewed Jun 13, 2017

View reviewed changes

moiseev approved these changes Jun 13, 2017

View reviewed changes

jessesquires mentioned this pull request Jun 14, 2017

[74] Issue #74 - June 15, 2017 SwiftWeekly/swiftweekly.github.io#267

Closed

airspeedswift merged commit 46952ad into swiftlang:swift-4.0-branch Jun 14, 2017

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

[4.0] String performance optimizations #10223

[4.0] String performance optimizations #10223

Uh oh!

dabrahams commented Jun 13, 2017 •

edited

Loading

Uh oh!

dabrahams commented Jun 13, 2017

Uh oh!

dabrahams commented Jun 13, 2017

Uh oh!

dabrahams commented Jun 13, 2017

Uh oh!

moiseev Jun 13, 2017

Uh oh!

dabrahams Jun 13, 2017

Uh oh!

moiseev left a comment

Uh oh!

swift-ci commented Jun 13, 2017

Uh oh!

dabrahams commented Jun 13, 2017

Uh oh!

shahmishal commented Jun 13, 2017

Uh oh!

dabrahams commented Jun 14, 2017 •

edited

Loading

Uh oh!

Uh oh!

+                }
+              }
+              /*

[4.0] String performance optimizations #10223

[4.0] String performance optimizations #10223

Uh oh!

Conversation

dabrahams commented Jun 13, 2017 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

dabrahams commented Jun 13, 2017

Uh oh!

dabrahams commented Jun 13, 2017

Uh oh!

dabrahams commented Jun 13, 2017

Uh oh!

moiseev Jun 13, 2017

Choose a reason for hiding this comment

Uh oh!

dabrahams Jun 13, 2017

Choose a reason for hiding this comment

Uh oh!

moiseev left a comment

Choose a reason for hiding this comment

Uh oh!

swift-ci commented Jun 13, 2017

Build comment file:

Uh oh!

dabrahams commented Jun 13, 2017

Uh oh!

shahmishal commented Jun 13, 2017

Uh oh!

dabrahams commented Jun 14, 2017 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Uh oh!

dabrahams commented Jun 13, 2017 •

edited

Loading

dabrahams commented Jun 14, 2017 •

edited

Loading