[Webkit-unassigned] [Bug 67354] ValueProfile does not make it safe to introspect cell values after garbage collection

bugzilla-daemon at webkit.org bugzilla-daemon at webkit.org
Wed Aug 31 22:41:18 PDT 2011


https://bugs.webkit.org/show_bug.cgi?id=67354





--- Comment #8 from Filip Pizlo <fpizlo at apple.com>  2011-08-31 22:41:18 PST ---
This is the overhead of value profiling with this patch, with DFG turned off.  As in, it's the overhead that baseline (before tier-up) code will experience.


Benchmark report for SunSpider, V8, and Kraken.

VMs tested:
"TipOfTree" at /Volumes/Data/fromMiniMe/quinary/OpenSource/WebKitBuild/Release/jsc
"ValueProfileOff" at /Volumes/Data/fromMiniMe/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            ValueProfileOff                                 
SunSpider:
   3d-cube                                8.8595+-0.0179    !     9.2453+-0.0312       ! definitely 1.0435x slower
   3d-morph                               8.1416+-0.0307    ?     8.2134+-0.0447       ?
   3d-raytrace                            9.4134+-0.0248    !    10.4939+-0.0476       ! definitely 1.1148x slower
   access-binary-trees                    2.2512+-0.0197    !     2.5353+-0.0231       ! definitely 1.1262x slower
   access-fannkuch                       12.9424+-0.0835    !    13.6188+-0.0511       ! definitely 1.0523x slower
   access-nbody                           7.4584+-0.0102    !     8.0224+-0.0572       ! definitely 1.0756x slower
   access-nsieve                          3.8109+-0.0260    ?     3.8529+-0.0177       ? might be 1.0110x slower
   bitops-3bit-bits-in-byte               2.5576+-0.0398    !     2.6751+-0.0281       ! definitely 1.0459x slower
   bitops-bits-in-byte                    6.6623+-0.1132    ^     6.0954+-0.1115       ^ definitely 1.0930x faster
   bitops-bitwise-and                     4.1196+-0.0338    ?     4.1530+-0.0457       ?
   bitops-nsieve-bits                     5.6830+-0.0388    !     5.9572+-0.0279       ! definitely 1.0482x slower
   controlflow-recursive                  2.2253+-0.0410    !     2.5391+-0.0337       ! definitely 1.1410x slower
   crypto-aes                             7.1616+-0.0281    !     7.6889+-0.0542       ! definitely 1.0736x slower
   crypto-md5                             3.1589+-0.0465    !     3.4858+-0.0329       ! definitely 1.1035x slower
   crypto-sha1                            2.6565+-0.0305    !     2.9111+-0.0303       ! definitely 1.0958x slower
   date-format-tofte                     11.7682+-0.0902    !    12.1948+-0.0730       ! definitely 1.0362x slower
   date-format-xparb                      9.6990+-0.1297    ?    10.0291+-0.2465       ? might be 1.0340x slower
   math-cordic                            7.3453+-0.3298    ?     7.3599+-0.0501       ?
   math-partial-sums                     10.4958+-0.0438         10.4889+-0.0372       
   math-spectral-norm                     4.4546+-0.0169    !     4.7794+-0.0634       ! definitely 1.0729x slower
   regexp-dna                            12.0460+-0.1184    ?    12.0732+-0.1311       ?
   string-base64                          5.7189+-0.0666    !     6.0201+-0.0766       ! definitely 1.0527x slower
   string-fasta                           7.9478+-0.0248    !     8.0574+-0.0268       ! definitely 1.0138x slower
   string-tagcloud                       15.2231+-0.0732    ?    15.3147+-0.0470       ?
   string-unpack-code                    20.5997+-0.0690    !    20.9489+-0.1046       ! definitely 1.0170x slower
   string-validate-input                  7.0806+-0.0941    ?     7.2559+-0.1048       ? might be 1.0247x slower

   <arithmetic>                           7.6724+-0.0358    !     7.9235+-0.0279       ! definitely 1.0327x slower
   <geometric>                            6.5102+-0.0354    !     6.7849+-0.0279       ! definitely 1.0422x slower
   <harmonic>                             5.4322+-0.0355    !     5.7459+-0.0297       ! definitely 1.0577x slower

                                            TipOfTree            ValueProfileOff                                 
V8:
   crypto                               206.8537+-0.4849    !   221.1158+-0.9468       ! definitely 1.0689x slower
   deltablue                            267.2850+-0.8388    !   318.9918+-1.8254       ! definitely 1.1935x slower
   earley-boyer                         126.5721+-0.3546    !   139.5270+-0.5612       ! definitely 1.1024x slower
   raytrace                              86.8362+-1.7937    !    93.1722+-0.8733       ! definitely 1.0730x slower
   regexp                               131.3743+-0.5879    ?   132.2735+-0.5262       ?
   richards                             279.6937+-0.7931    !   312.9718+-1.1768       ! definitely 1.1190x slower
   splay                                155.0793+-1.1745    ?   157.0248+-1.3658       ? might be 1.0125x slower

   <arithmetic>                         179.0992+-0.4639    !   196.4396+-0.5115       ! definitely 1.0968x slower
   <geometric>                          165.9162+-0.6798    !   179.3075+-0.4987       ! definitely 1.0807x slower
   <harmonic>                           153.3871+-0.9578    !   163.9957+-0.5743       ! definitely 1.0692x slower

                                            TipOfTree            ValueProfileOff                                 
Kraken:
   ai-astar                            2072.9013+-30.9877   !  2196.3937+-15.3871      ! definitely 1.0596x slower
   audio-beat-detection                 539.6634+-2.2724    !   568.2251+-1.1907       ! definitely 1.0529x slower
   audio-dft                            454.8677+-4.2642    !   488.1209+-3.1658       ! definitely 1.0731x slower
   audio-fft                            421.0421+-0.9320    !   442.3705+-0.5048       ! definitely 1.0507x slower
   audio-oscillator                     379.6714+-5.3440    !   411.9139+-1.8822       ! definitely 1.0849x slower
   imaging-darkroom                     590.8199+-7.1784    ?   597.6895+-3.8731       ? might be 1.0116x slower
   imaging-desaturate                   617.4223+-2.4087    !   649.5490+-4.5528       ! definitely 1.0520x slower
   imaging-gaussian-blur               2176.1665+-7.1226    !  2388.3892+-8.3513       ! definitely 1.0975x slower
   json-parse-financial                  61.9086+-0.2256    !    62.5446+-0.2643       ! definitely 1.0103x slower
   json-stringify-tinderbox              76.1372+-0.2654         75.5563+-0.3188       
   stanford-crypto-aes                  166.0477+-0.6312    !   181.3763+-0.5867       ! definitely 1.0923x slower
   stanford-crypto-ccm                  132.4801+-1.1672    !   143.9892+-0.2739       ! definitely 1.0869x slower
   stanford-crypto-pbkdf2               434.5020+-2.4759    !   441.8006+-2.5230       ! definitely 1.0168x slower
   stanford-crypto-sha256-iterative     160.7851+-0.5561    !   165.1758+-0.5175       ! definitely 1.0273x slower

   <arithmetic>                         591.7440+-2.0751    !   629.5067+-1.1978       ! definitely 1.0638x slower
   <geometric>                          353.0441+-0.4950    !   370.7383+-0.4695       ! definitely 1.0501x slower
   <harmonic>                           216.3901+-0.4013    !   223.6948+-0.3026       ! definitely 1.0338x slower

                                            TipOfTree            ValueProfileOff                                 
All benchmarks:
   <arithmetic>                         207.1828+-0.6364    !   221.1528+-0.3620       ! definitely 1.0674x slower
   <geometric>                           34.6434+-0.1193    !    36.3830+-0.0929       ! definitely 1.0502x slower
   <harmonic>                             9.5985+-0.0615    !    10.1506+-0.0515       ! definitely 1.0575x slower

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