Bug 67554

Summary: DFG variable predictions only work for local variables, not temporaries
Product: WebKit Reporter: Filip Pizlo <fpizlo>
Component: JavaScriptCoreAssignee: Nobody <webkit-unassigned>
Status: RESOLVED FIXED    
Severity: Normal CC: webkit.review.bot
Priority: P2    
Version: 528+ (Nightly build)   
Hardware: All   
OS: All   
Attachments:
Description Flags
the patch none

Filip Pizlo
Reported 2011-09-02 23:14:29 PDT
The local variable prediction code in DFG::Graph does not work for temporaries, even though it easily could, and probably should. This causes speculation logic to be overly conservative if a temporary is live across multiple basic blocks.
Attachments
the patch (1.84 KB, patch)
2011-09-02 23:18 PDT, Filip Pizlo 		no flags
DetailsFormatted DiffDiff
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Filip Pizlo
Comment 1 2011-09-02 23:18:14 PDT
Created attachment 106247 [details] the patch
Filip Pizlo
Comment 2 2011-09-02 23:21:39 PDT
This is the performance: Benchmark report for SunSpider, V8, and Kraken. VMs tested: "TipOfTree" at /Volumes/Data/pizlo/quinary/OpenSource/WebKitBuild/Release/jsc "ResizeVarPreds" at /Volumes/Data/pizlo/septenary/OpenSource/WebKitBuild/Release/jsc Collected 12 samples per benchmark/VM, with 4 VM invocations per benchmark. Used 1 benchmark iteration per VM invocation for warm-up. Used the jsc-specific preciseTime() function to get microsecond-level timing. Reporting benchmark execution times with 95% confidence intervals in milliseconds. TipOfTree ResizeVarPreds SunSpider: 3d-cube 8.0769+-0.2633 7.8421+-0.1866 might be 1.0299x faster 3d-morph 7.9217+-0.1421 ^ 7.6166+-0.1522 ^ definitely 1.0401x faster 3d-raytrace 7.5407+-0.2822 ? 7.5764+-0.1596 ? access-binary-trees 2.3041+-0.0434 2.2708+-0.0502 might be 1.0147x faster access-fannkuch 11.9338+-0.2432 11.9160+-0.2582 access-nbody 4.2317+-0.0457 ? 4.3202+-0.0630 ? might be 1.0209x slower access-nsieve 2.6031+-0.1330 2.5357+-0.0514 might be 1.0266x faster bitops-3bit-bits-in-byte 1.7767+-0.0823 1.7109+-0.0568 might be 1.0385x faster bitops-bits-in-byte 4.5004+-0.1841 ? 4.6038+-0.2552 ? might be 1.0230x slower bitops-bitwise-and 3.7526+-0.1117 3.7345+-0.0547 bitops-nsieve-bits 5.4707+-0.1478 ? 5.5343+-0.1609 ? might be 1.0116x slower controlflow-recursive 2.0275+-0.0386 ? 2.1304+-0.0970 ? might be 1.0507x slower crypto-aes 6.5957+-0.1562 6.5791+-0.1279 crypto-md5 2.7703+-0.0633 2.7343+-0.0570 might be 1.0132x faster crypto-sha1 2.3163+-0.0783 2.2194+-0.0506 might be 1.0437x faster date-format-tofte 10.3854+-0.2497 ? 10.3987+-0.3102 ? date-format-xparb 8.8015+-0.2505 8.7822+-0.2139 math-cordic 6.4468+-0.0492 ? 6.4918+-0.0753 ? math-partial-sums 8.1159+-0.2666 7.8487+-0.2188 might be 1.0340x faster math-spectral-norm 2.5621+-0.0720 2.5355+-0.0520 might be 1.0105x faster regexp-dna 10.3926+-0.0760 ? 10.4463+-0.1122 ? string-base64 6.1697+-0.2178 ? 6.2009+-0.2772 ? string-fasta 7.5724+-0.1146 7.4252+-0.1236 might be 1.0198x faster string-tagcloud 12.3140+-0.4933 12.2323+-0.2761 string-unpack-code 18.9475+-0.4868 ? 19.3867+-0.4740 ? might be 1.0232x slower string-validate-input 7.4412+-0.2151 ? 7.4739+-0.2596 ? <arithmetic> 6.6527+-0.0453 6.6364+-0.0350 <geometric> 5.5332+-0.0355 5.5064+-0.0282 <harmonic> 4.5285+-0.0383 4.4957+-0.0263 TipOfTree ResizeVarPreds V8: crypto 92.3651+-0.3348 92.3497+-0.5405 deltablue 144.0207+-0.8783 143.1391+-1.0990 earley-boyer 100.5560+-0.5754 ? 100.5589+-0.5720 ? raytrace 52.9002+-0.3640 52.4050+-0.3120 regexp 111.1890+-0.4171 ? 111.7704+-0.8885 ? richards 246.2668+-0.7304 ? 249.7471+-4.0842 ? might be 1.0141x slower splay 104.8678+-0.6789 ? 104.9036+-0.6532 ? <arithmetic> 121.7380+-0.2460 ? 122.1249+-0.5218 ? <geometric> 110.6561+-0.2208 ? 110.7121+-0.2636 ? <harmonic> 101.1378+-0.2360 100.9628+-0.2184 TipOfTree ResizeVarPreds Kraken: ai-astar 1117.1826+-7.3669 1107.8483+-4.7591 audio-beat-detection 479.5615+-1.5012 ? 481.1826+-1.6781 ? audio-dft 437.8244+-5.0489 ? 439.3640+-3.1897 ? audio-fft 373.5425+-0.4485 ? 373.8119+-1.7038 ? audio-oscillator 386.2704+-2.5483 385.2089+-1.5145 imaging-darkroom 560.4767+-1.9983 ^ 553.5504+-1.7509 ^ definitely 1.0125x faster imaging-desaturate 601.5663+-7.9396 600.6047+-6.4242 imaging-gaussian-blur 1756.0249+-3.8117 ? 1760.0847+-4.2614 ? json-parse-financial 48.0583+-0.4829 ? 48.1131+-0.2504 ? json-stringify-tinderbox 73.4140+-0.3952 ? 73.4151+-0.3149 ? stanford-crypto-aes 148.1695+-2.6645 146.9939+-0.8603 stanford-crypto-ccm 118.6461+-4.4542 ^ 113.2232+-0.5431 ^ definitely 1.0479x faster stanford-crypto-pbkdf2 351.8983+-2.5204 348.3458+-1.5261 might be 1.0102x faster stanford-crypto-sha256-iterative 134.3091+-0.8045 ^ 132.5642+-0.6250 ^ definitely 1.0132x faster <arithmetic> 470.4960+-1.0338 ^ 468.8793+-0.5025 ^ definitely 1.0034x faster <geometric> 304.3833+-1.0155 ^ 302.4315+-0.3470 ^ definitely 1.0065x faster <harmonic> 187.9824+-0.9233 ^ 186.6012+-0.3609 ^ definitely 1.0074x faster TipOfTree ResizeVarPreds All benchmarks: <arithmetic> 161.9592+-0.3159 161.5262+-0.1479 <geometric> 28.5211+-0.1086 28.3923+-0.0794 <harmonic> 7.9863+-0.0660 7.9289+-0.0452
Filip Pizlo
Comment 3 2011-09-02 23:33:44 PDT
Comment on attachment 106247 [details] the patch Passes tests.
WebKit Review Bot
Comment 4 2011-09-03 00:48:21 PDT
Comment on attachment 106247 [details] the patch Clearing flags on attachment: 106247 Committed r94484: <http://trac.webkit.org/changeset/94484>
WebKit Review Bot
Comment 5 2011-09-03 00:48:25 PDT
All reviewed patches have been landed. Closing bug.
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