性能优化 之 无分支编程 Branchless Programming by 彭于斌（ @archibate ） 两种代码写法：分支 vs 三目运算符 两种使用方式：排序 vs 不排序 测试结果（均为 gcc -O3 ） 测试结果可视化 图表比较：分支 vs 无分支 分支 无分支 0 0.01 0.02 0.03 耗时（越低越好） 乱序 有序 • 传统的分支方法实现的

abstract software entity, and accidental tasks, the representation of the abstract entities in programming languages and the mapping of these onto machine languages within space and speed constraints have made the accidental tasks inordinately hard, such as severe hardware constraints, awkward programming languages, lack of machine time. How much of what software engineers now do is still devoted • Preserves immediacy, and hence enables us to maintain an overview of complexity • Unified programming environment • They attack the accidental difficulties of using tools togetherHopes for the Silver“Now

Foundations of the Rust Programming Language. In POPL 2018: ACM SIGPLAN Symposium on Principles of Programming Languages Ralf Jung. Understanding and Evolving the Rust Programming Language. PhD dissertation Dissertation Award Recipient of the 2021 Otto Hahn Medal Ralf Jung Assistant professor, Institute for Programming Languages and Systems, ETH Zürich RustBelt Project Background Iris: A Higher-Order Concurrent Concurrent Separation Logic Framework RustBelt: Securing the Foundations of the Rust Programming Language Coq Proof Assistant: A Formal Proof Management System built on top of built on top of Rust Types

now Cryptape Rust My work experience • Strongly interested in programming languages implementation • My solutions to EOPL My experience • 2014 ~ 2018 Some small 年写一本编程语言实现的书 Crafting Interpreters • Essentials of Programming Languages • rui314/9cc: A Small C Compiler Great resources for programming languages Thank you ！

to C • Memory management without garbage collection • Designed for systems programming Rust is a multi-paradigm programming language focused on performance and safety, especially safe concurrency. empty

more memory • One test case panics, crashes all the other AT jobs • High maintenance due to programming language 大公司 API 测试的需求 软件测试工具 • 模拟数据规则 • 自动化测试 • Use rust to compile wasm and send to wasm exhaust memory • A test suite panic will not implicate the others • Can be compiled from many programming language • Store wasm files prevent maintenance issues API 测试 - Wasm Mock Server 用 rust, 好处多

noexcept;11 constexpr Algorithms12 C++20 constexpr Everything • constexpr enables compile-time programming without arcane templates • Algorithms: • P0202R3 constexpr And exchange() (GH-425) Containers • GH-43 P0980R1 constexpr string • GH-45 P1004R2 constexpr vector13 constexpr In Everyday Programming • constexpr has steadily increased in power • It's just code that runs on your machine instead

Executed on the device, • Callable from the device only. https://docs.nvidia.com/cuda/cuda-c-programming-guide/ index.html#function-declaration-specifiers 36 |The __host__ execution space specifier either case the function is compiled for the host only. https://docs.nvidia.com/cuda/cuda-c-programming-guide/index.html#host Execution Space Specifiers 37 |__host__ __device__ void _add(std::size_t

reclamation, i.e., garbage collection in C++ Some assumed knowledge • You’ve heard of lock-free programming and know what a compare_exchange is • You know roughly what atomic does and what it is used for reclamation, i.e., garbage collection in C++ Some assumed knowledge • You’ve heard of lock-free programming and know what a compare_exchange is • You know roughly what atomic does and what it is used for

Questions A little about me • Developer of the NativeScript.rocks sites: • > 20 years doing programming and DevOps • > 20 Languages and many OS’s • > 30 NativeScript Plugins • Wrote books on NativeScript