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![Assembly Language
mov rax, 05H
mov rbx, 0AH
add rax, rbx
mov rax, [1000]](https://image.slidesharecdn.com/turbochargingv8engine-160213100013/85/Turbo-charging-v8-engine-11-320.jpg)
![JIT
iconst 5
set a
iconst 10
set b
push a
push b
add
set c
mov rax, 05H
mov rbx, 0AH
add rax, rbx
mov rax, [1000]
At Runtime](https://image.slidesharecdn.com/turbochargingv8engine-160213100013/85/Turbo-charging-v8-engine-20-320.jpg)
![Assembly Language
mov rax, 05H
mov rbx, 0AH
add rax, rbx
mov rax, [1000]](https://image.slidesharecdn.com/turbochargingv8engine-160213100013/75/Turbo-charging-v8-engine-11-2048.jpg)
![JIT
iconst 5
set a
iconst 10
set b
push a
push b
add
set c
mov rax, 05H
mov rbx, 0AH
add rax, rbx
mov rax, [1000]
At Runtime](https://image.slidesharecdn.com/turbochargingv8engine-160213100013/75/Turbo-charging-v8-engine-20-2048.jpg)
Uploaded byHyderabad Scalability Meetup
Turbo charging v8 engine
This document discusses ways to optimize JavaScript performance using the V8 engine. It describes how V8 compiles JavaScript using various techniques like full code generation, inline caching, and just-in-time compilation to generate highly optimized machine code. It provides tips for writing JavaScript code that works well with V8's optimizations, such as using homogeneous data types and pre-allocating arrays. The goal is to allow JavaScript applications to achieve performance close to fully compiled languages like C++.
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Turbo charging v8 engine
- 1. Turbocharging JavaScript: V8 Rahul Dé CompilerJunkie @ThoughtWorks
- 2. Problem Find the 25,000th Prime number
- 3.
- 4. The Language Invented byBrendan Eich at Mozilla Research. Defined by the ECMA 262 Standard - ECMAScript 6. Dynamically Typed. Duck Typing. Prototype and Object based. Asynchrony is a language feature. Functions are first class citizens. Has its fair share of the Good, the Bad and the Ugly.
- 5. Implementing the Good, Badand the Ugly.
- 6. Major JavaScript Implementations SpiderMonkey, IonMonkeyand JägerMonkey JIT compilers by Mozilla powering Firefox. V8 by Google powering the Chromium family of Browsers, Opera, Node.js, MongoDB etc. JSCore by Apple powering Safari and WebKit based browsers. Rhino/Nashorn by Mozilla Research and Oracle implement JavaScript in the JVM.
- 7. Fully Compiled Languages C, C++, Pascal,Fortan etc…
- 8.
- 9.
- 10. Intermediate Representation int a =5; int b = 10; int c = a + b; stor a, 5 mov r1, a stor b, 10 mov r2, 10 add r1, r2 store c, r1
- 11. Assembly Language mov rax,05H mov rbx, 0AH add rax, rbx mov rax, [1000]
- 12.
- 13. Tokenize r Parser Optimize r Gramma r Code Gen ByteCode Tokens AST VM
- 14. Byte Codes a =5; b = 10; c = a + b; iconst 5 set a iconst 10 set b push a push b add set c
- 15. Virtual Machines Stack VM- JVM, Python VM, Ruby VM(YARV) etc. Register VM - Dalvik VM, Lua VM, LLVM etc.
- 16. Running Byte codes iconst5 set a iconst 10 set b push a push b add set c 5 pop 10 pop a a b a + b pop a = 5 b = 10 c = 15
- 17. Problems?? A full programexecutes them Lot of context switching A big switch case to dispatch the byte codes Big libs to handle the ops But, necessary as its a dynamic language and makes it cross platform
- 18.
- 19. Tokenize r Parser Optimize r Gramma r Code Gen ByteCode Tokens AST VM JIT
- 20. JIT iconst 5 set a iconst10 set b push a push b add set c mov rax, 05H mov rbx, 0AH add rax, rbx mov rax, [1000] At Runtime
- 21. Why code directly executeson CPU hence MUCH faster no need of complex slow code to dispatch byte codes more efficient execution with lesser machine resources used. Enables much more runtime optimizations but is quite difficult to implement
- 22. Can JavaScript everbe faster than C++?
- 26. Features NO BYTECODES! Full RegisterJIT Advanced runtime/compile time optimizations Highly embeddable Implements the full ES6 spec
- 27. Architecture and Design Compile r FullCode Gen Crankshaft Compiler Hydrogen DFG Lithium IR Optimized Code Gen Inline Caches
- 28. Compiler Reads the JavaScript source. Tokenizes,Parses and checks for syntax errors. Produces a persistant AST or pAST. Very VERY fast.
- 29. Full Code Gen Readsthe AST Blindly generates platform specific assembly code. Generates some extra code to infer types called inline caches (IC). Dispatches whole code to CPU directly. Very VERY VERY fast.
- 30. Inline Caches (IC) functionadd(a, b) { return a + b; } add(5, 6) add(“5”, 6) add(“Rahul”, “Dé”) int, int -> int str, int -> str str, str -> str asm1 asm2 asm3 Call Sites
- 31. Crankshaft Compiler Profiles theCPU performance via a thread. Gathers type info from the ICs. Generates the Hydrogen representation for advanced optimizations From that generates platform specific Lithium IR for register allocation with more optimizations. Finally super fast, optimized assembly is generated and is set free on the CPU. De-optimizes wrongly optimized code to full code gen level. Crankshaft is slower than others as it does a lot of analysis.
- 32. Hydrogen DFG Derived fromtype info from the ICs. Is a Acyclic Data Flow Graphical Representation of the pAST. Enables advanced optimizations like hotspots, unreachable code, peep hole, loop invariant code motions etc. Used to generate the platform specific Lithium code.
- 33. Lithium IR Is athree address register representation of the Hydrogen DFG Enables low level optimizations like register reduction Maps exactly to the underlying architecture to maximize faster code gen. Used to generate the fast optimized native assembly code.
- 34. Possible Future ofV8 Ignition Compiler Much faster and produces streamlined, compact byte codes which saves a lot of memory with at par perf. Turbofan Engine Reads the ignition byte codes and JITs directly with blazing fast speed while reducing memory footprints. Replace the pAST, full code gen and crankshaft with the ignition and turbofan compilers. Already in pre Alpha builds.
- 35. Can I helpV8 to execute my code better??
- 36. Of course. Bynow you know a lot about V8. And definitely you can now write much better code.
- 37.
- 38. Hidden Classes function Point(x,y) { this.x = x; this.y = y; } var p1 = new Point(5, 6); var p2 = new Point(7, 8); x y x 5 y 6 x 7 y 8
- 39. Hidden Classes var p1= new Point(5, 6); p1.z = 4; delete p1.z; x y x y z x 5 y 6 z 4
- 40. Performance Tips Try touse homogeneous data types in Arrays. Pre allocate arrays if non homogeneous data is needed. Avoid pushing non homogenous types like bools into int arrays. Initialize Function objects instead of pushing in attributes later on. Catch blocks are not crankshaft optimizable, write the catch code in a function and call it from the catch block.
- 41.
- 42. Fixing the Problem Findthe 25, 000th Prime number
- 43.