[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 13:29:42 PDT 2011


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





--- Comment #1 from Filip Pizlo <fpizlo at apple.com>  2011-09-08 13:29:42 PST ---
This is a work in progress, and isn't totally stable yet.  It's also a regression on v8-crypto under static speculation (which is still the default in ToT).



Benchmark report for SunSpider and V8.

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                        7.8561+-0.1646          7.8155+-0.2022       
   3d-morph                       7.8473+-0.1579          7.6001+-0.1902         might be 1.0325x faster
   3d-raytrace                    7.6863+-0.1967          7.6497+-0.2789       
   access-binary-trees            2.2991+-0.0437    ?     2.3556+-0.0766       ? might be 1.0245x slower
   access-fannkuch               12.0374+-0.2866         11.8132+-0.1643         might be 1.0190x faster
   access-nbody                   4.4257+-0.1024          4.3487+-0.0582         might be 1.0177x faster
   access-nsieve                  2.5066+-0.0831    ?     2.5857+-0.0715       ? might be 1.0316x slower
   bitops-3bit-bits-in-byte       1.7548+-0.0479    ?     1.7602+-0.0528       ?
   bitops-bits-in-byte            4.5568+-0.2521    ?     4.6508+-0.2218       ? might be 1.0206x slower
   bitops-bitwise-and             3.7287+-0.0639    ?     3.7565+-0.0750       ?
   bitops-nsieve-bits             5.5253+-0.1456    ?     5.6534+-0.1690       ? might be 1.0232x slower
   controlflow-recursive          2.0740+-0.0461          2.0333+-0.0497         might be 1.0200x faster
   crypto-aes                     6.9185+-0.3649          6.8543+-0.3203       
   crypto-md5                     2.8268+-0.0863    ?     2.8695+-0.1142       ? might be 1.0151x slower
   crypto-sha1                    2.2198+-0.0391    !     2.3437+-0.0718       ! definitely 1.0558x slower
   date-format-tofte             10.4411+-0.3354         10.1745+-0.2410         might be 1.0262x faster
   date-format-xparb              9.1471+-0.2291    ?     9.1878+-0.2066       ?
   math-cordic                    6.4154+-0.1277          6.2871+-0.1184         might be 1.0204x faster
   math-partial-sums              7.9001+-0.1389          7.8879+-0.1401       
   math-spectral-norm             2.5591+-0.0447    ^     2.4600+-0.0321       ^ definitely 1.0403x faster
   regexp-dna                    10.5650+-0.2633    ?    10.5712+-0.1567       ?
   string-base64                  6.0538+-0.1903    ?     6.1351+-0.2088       ? might be 1.0134x slower
   string-fasta                   7.6601+-0.2406    ?     7.6878+-0.1736       ?
   string-tagcloud               12.2444+-0.3531         12.1599+-0.2803       
   string-unpack-code            18.9348+-0.3692    ?    19.0148+-0.3475       ?
   string-validate-input          7.2754+-0.2723          7.2458+-0.2474       

   <arithmetic>                   6.6715+-0.0391          6.6501+-0.0287       
   <geometric>                    5.5415+-0.0294          5.5415+-0.0278       
   <harmonic>                     4.5240+-0.0279    ?     4.5413+-0.0278       ?

                                    TipOfTree            PartialSpecFail                                 
V8:
   crypto                        91.7346+-0.8852    !   100.1585+-0.5619       ! definitely 1.0918x slower
   deltablue                    270.8549+-2.1356        267.9829+-1.3881         might be 1.0107x faster
   earley-boyer                  95.2392+-0.6167    !    97.1235+-0.8832       ! definitely 1.0198x slower
   raytrace                      80.0969+-0.8197         79.2897+-0.3222         might be 1.0102x faster
   regexp                       112.4222+-1.1974        111.2879+-0.7193         might be 1.0102x faster
   richards                     246.1516+-1.8007    ^   240.0536+-0.7336       ^ definitely 1.0254x faster
   splay                        103.9291+-0.3727    ?   104.3902+-1.1212       ?

   <arithmetic>                 142.9183+-0.5466        142.8981+-0.2484       
   <geometric>                  127.4043+-0.3828    !   128.4276+-0.2773       ! definitely 1.0080x slower
   <harmonic>                   116.3446+-0.3055    !   117.9230+-0.2941       ! definitely 1.0136x slower

                                    TipOfTree            PartialSpecFail                                 
All benchmarks:
   <arithmetic>                  35.5724+-0.1334         35.5512+-0.0619       
   <geometric>                   10.7755+-0.0479    ?    10.7938+-0.0442       ?
   <harmonic>                     5.6825+-0.0347    ?     5.7048+-0.0345       ?

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