Lucet: A Compiler and Runtime for High-Concurrency Low-Latency Sandboxing
summary
Lucet is an ahead-of-time WebAssembly compiler and runtime that Fastly uses to run user code with Cranelift codegen and an artifact contract that guarantees memory layout and imports. It tiles fixed-size virtual-memory regions into slots to start instances in about 50 microseconds startup, supports millions of requests per second and enables guard-page bounds-check elision for faster stores. It works in production but still wrestles with host–guest protocol bugs, fairness of resource accounting and defenses against transient-execution attacks.
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chapters (38)
- 0:00Introduction
- 0:35Qualifications
- 1:33Personality
- 2:20Context
- 4:23Architecture
- 5:07Pop Distribution
- 6:50Functions as a Service
- 8:33In an ideal world
- 9:57Common practice
- 12:01Sandbox
- 17:15Project History
- 18:36Project Goals
- 19:39What is a compiler
- 20:03What is a parser
- 20:17What is a translator
- 20:38What is an artifact
- 21:37Code Generator
- 21:48Optimizer
- 22:53Runtime
- 23:33Runtime Components
- 25:29WebAssembly
- 25:55Heap
- 26:05WebAssembly Spec
- 27:08Bounce Check
- 27:42Pointer Length
- 27:59Bounce Checks
- 29:09Context Switch
- 30:47Memory Layout
- 31:03Memory Layout Example
- 35:59Memory Manager
- 36:40Limitations
- 36:53Protection
- 37:38Safety
- 39:06Fairness
- 41:23Transient Execution Attacks
- 42:49Industry Context
- 44:47Memory Security
- 52:29Attacks
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