Moving Node.js and nodec to v8 Ignition

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1. Moving Node.js and nodec to Ignition Minqi Pan
2. Chromium #593477 Open Chrome 51 (canary) (1) Load www.facebook.com multiple times in the browser (2) exit the browser, open about:tracing and record all enabled by default categories
3. Chromium #593477 Result: (1) initial load, v8.CompileScript takes 165 ms (2) repeated loads, V8.ParseLazy takes 376 ms
4. Chromium #593477 Why? - Entirely compile eagerly are too costly (Being included in the code cache increases both the footprint on the hard disk and takes longer to serialize and deserialize. let alone the memory…) - So only the toplevel code gets compiled - Functions contained is compiled until the function is actually called - Lazily compiling inner functions still requires a new parsing pass
5. Facebook uses a transpiler to combine individual modules into a single file. E.g. Chromium #593477
6. Motivation • Memory (major motivator) • Startup Speed • simpler script execution pipeline; reduce jank; make the interchange between V8’s various components more efficient; support ES2015+
7. Old Architecture
8. Multiple Parsing Machine Code
9. might never run again N-level-nested function is parsed N times
10. New Architecture
11. Memory Problem JIT-ed code
12. Memory Optimized
13. Mobile Top 10 Benchmark
15. run-once or non-hot code now stored more compactly in bytecode form
16. Startup Speed Problem actual executing
17. Startup Speed Optimized
18. v8 Bytecode design goals • Concise • … so that Bytecode size have a small memory footprint (machine code generated by V8’s full- codegen compiler is verbose) • … so that we always compile it eagerly • … so that initial startup is faster
19. e.g. accumulator register • implicit register for many bytecodes to hold temporary results • avoiding the need to specify specific register operands, reduces the size of bytecodes • many JavaScript expressions involve chains of operations
20. Comparing with the others
21. BE & FE differences • FE has limited battery, memory, network resources. • FE usually won’t ship a lot of unused code • BE has big node_modules folder so cost of eagerly compiling all is still huge • BE has mmap, though…mmap works good on a single file, though…
22. 去吧！Node.js Compiler
23. w/ Node.js Compiler • Eagerly compile everything into Bytecode, including node_modules • Put them inside a SquashFS (i.e. your.exe) • Mmap SquashFS (i.e. your.exe) when executed • Enjoy low memory footprint AND fast startup, while avoiding multiple parsings, even no source shipped • End-product got bigger. Who cares? (this is not FE)
24. December 2, 2016 V8 5.6 Released Ignition and TurboFan pipeline shipped
25. February 6, 2017 V8 5.7 Released
26. March 20, 2017 V8 5.8 Released
27. Apr. 19, 2017 V8 5.8 shipped in Chrome 58
28. A/B Test in progress
29. A/B Test in progress
30. How about Node.js? node date v8 6.10.2 2017-04-04 5.1.281.98 7.9.0 2017-04-11 5.5.372.43
32. Future Node.js node date v8 8.0.0 2017-05-30 5.8 8.x.0 2017-06 5.9 8.y.0 2017-08 6.0