[Webkit-unassigned] [Bug 67798] DFG JIT completely undoes speculative compilation even in the case of a partial static speculation failure

bugzilla-daemon at webkit.org bugzilla-daemon at webkit.org
Thu Sep 8 14:15:07 PDT 2011


https://bugs.webkit.org/show_bug.cgi?id=67798





--- Comment #2 from Filip Pizlo <fpizlo at apple.com>  2011-09-08 14:15:07 PST ---
This now appears stable.  But, it's a V8 slow-down.



Benchmark report for SunSpider, V8, and Kraken.

VMs tested:
"TipOfTree" at /Volumes/Data/pizlo/quinary/OpenSource/WebKitBuild/Release/jsc
"PartialSpecFail" at /Volumes/Data/pizlo/octonary/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            PartialSpecFail                                 
SunSpider:
   3d-cube                                7.8790+-0.1847          7.7234+-0.2069         might be 1.0202x faster
   3d-morph                               7.8556+-0.1429    ^     7.4219+-0.1409       ^ definitely 1.0584x faster
   3d-raytrace                            7.5771+-0.2102          7.5468+-0.1384       
   access-binary-trees                    2.2669+-0.0389    ?     2.2928+-0.0555       ? might be 1.0114x slower
   access-fannkuch                       11.9656+-0.2655    ?    11.9976+-0.2837       ?
   access-nbody                           4.3613+-0.1447          4.2937+-0.0866         might be 1.0157x faster
   access-nsieve                          2.4939+-0.0718    ?     2.5792+-0.0601       ? might be 1.0342x slower
   bitops-3bit-bits-in-byte               1.7326+-0.0618    ?     1.8014+-0.0547       ? might be 1.0397x slower
   bitops-bits-in-byte                    4.6134+-0.2415    ^     3.3414+-0.1481       ^ definitely 1.3807x faster
   bitops-bitwise-and                     3.7141+-0.0795          3.6939+-0.0653       
   bitops-nsieve-bits                     5.5147+-0.1153          5.4464+-0.1066         might be 1.0125x faster
   controlflow-recursive                  2.0409+-0.0581    ?     2.0611+-0.0426       ?
   crypto-aes                             6.5953+-0.1324          6.5248+-0.1913         might be 1.0108x faster
   crypto-md5                             2.7708+-0.0604          2.7644+-0.0653       
   crypto-sha1                            2.3058+-0.0905          2.2729+-0.0468         might be 1.0145x faster
   date-format-tofte                     10.5226+-0.3112         10.2755+-0.3134         might be 1.0240x faster
   date-format-xparb                      8.8497+-0.3011    ?     9.0041+-0.2844       ? might be 1.0175x slower
   math-cordic                            6.3786+-0.1561          6.3529+-0.1171       
   math-partial-sums                      7.8715+-0.1752          7.7494+-0.1679         might be 1.0157x faster
   math-spectral-norm                     2.5403+-0.0564    ?     2.5837+-0.1298       ? might be 1.0171x slower
   regexp-dna                            10.5271+-0.1745         10.3552+-0.2115         might be 1.0166x faster
   string-base64                          6.1475+-0.2276          6.0770+-0.2383         might be 1.0116x faster
   string-fasta                           7.7278+-0.2546          7.5394+-0.1755         might be 1.0250x faster
   string-tagcloud                       12.1584+-0.4519    ?    12.2708+-0.3747       ?
   string-unpack-code                    18.6953+-0.4765    ?    19.0792+-0.4617       ? might be 1.0205x slower
   string-validate-input                  7.2421+-0.2037          7.0584+-0.1706         might be 1.0260x faster

   <arithmetic>                           6.6288+-0.0408    ^     6.5426+-0.0404       ^ definitely 1.0132x faster
   <geometric>                            5.5099+-0.0338    ^     5.4210+-0.0341       ^ definitely 1.0164x faster
   <harmonic>                             4.4992+-0.0305          4.4473+-0.0353         might be 1.0117x faster

                                            TipOfTree            PartialSpecFail                                 
V8:
   crypto                                91.0338+-0.5191    !   104.1613+-0.8925       ! definitely 1.1442x slower
   deltablue                            269.7535+-2.7809    ^   265.7885+-0.7118       ^ definitely 1.0149x faster
   earley-boyer                          95.0161+-0.5041    ?    95.5356+-0.5577       ?
   raytrace                              79.1499+-0.5473    ?    79.7137+-0.6612       ?
   regexp                               110.8495+-0.4558    ^   109.2641+-0.3574       ^ definitely 1.0145x faster
   richards                             240.9133+-0.8254        239.4367+-1.6783       
   splay                                103.0647+-0.6429    !   104.4789+-0.7212       ! definitely 1.0137x slower

   <arithmetic>                         141.3972+-0.2966    !   142.6256+-0.4231       ! definitely 1.0087x slower
   <geometric>                          126.1408+-0.1666    !   128.4242+-0.3937       ! definitely 1.0181x slower
   <harmonic>                           115.2637+-0.1753    !   118.0846+-0.4050       ! definitely 1.0245x slower

                                            TipOfTree            PartialSpecFail                                 
Kraken:
   ai-astar                            1108.9297+-5.9845    ?  1123.4756+-12.5830      ? might be 1.0131x slower
   audio-beat-detection                 481.1936+-1.4541    ?   486.0185+-4.7695       ? might be 1.0100x slower
   audio-dft                            426.4858+-4.3795        425.2002+-2.3276       
   audio-fft                            373.8409+-2.1670    ?   374.6652+-0.9116       ?
   audio-oscillator                     384.1150+-2.2719    ?   387.0932+-3.3490       ?
   imaging-darkroom                     537.6787+-3.3081        534.4603+-2.0673       
   imaging-desaturate                   623.8627+-8.2803        615.4398+-4.8321         might be 1.0137x faster
   imaging-gaussian-blur               1738.3217+-5.4653       1729.6538+-4.2880       
   json-parse-financial                  49.1108+-0.5305    ?    49.8053+-0.3037       ? might be 1.0141x slower
   json-stringify-tinderbox              72.4905+-0.6863    ^    69.0171+-0.4305       ^ definitely 1.0503x faster
   stanford-crypto-aes                  145.4706+-1.1861        145.0223+-1.1645       
   stanford-crypto-ccm                  115.7358+-0.3964    ^   113.6545+-0.7748       ^ definitely 1.0183x faster
   stanford-crypto-pbkdf2               338.3754+-1.7782    !   341.7524+-1.4837       ! definitely 1.0100x slower
   stanford-crypto-sha256-iterative     131.3300+-0.4891    !   134.3038+-1.2092       ! definitely 1.0226x slower

   <arithmetic>                         466.2101+-0.8557    ?   466.3973+-1.1839       ?
   <geometric>                          301.2570+-0.3548        300.8576+-0.4784       
   <harmonic>                           186.9324+-0.3719    ^   186.0068+-0.4899       ^ definitely 1.0050x faster

                                            TipOfTree            PartialSpecFail                                 
All benchmarks:
   <arithmetic>                         163.5972+-0.2484    ?   163.7883+-0.3213       ?
   <geometric>                           28.9262+-0.1040         28.7323+-0.1022       
   <harmonic>                             7.9467+-0.0525          7.8585+-0.0613         might be 1.0112x faster

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