Ruby with BPF eBPF Summit ## Why BPF? ## Why BPF? ## - Flexibility ## Why BPF? - Flexibility - Low overhead ## Why BPF? - Flexibility - Low overhead - Continuous profiling ## Why BPF? - Flexibility stack walking for a dynamic language - Supporting multiple Ruby versions - Correctness testing - BPF safety features ## Future plans - Integrate in Facebook’s profiling infra - Rewrite OSS driver program

## Containers and BPF: twagent story Andrey Ignatov, Facebook eBPF Summit ## twagent • a daemon - runs on every Facebook server • manages all Facebook containers - a part of the bigger TW system cgroup v2 • ... other usual building blocks ... • cgroup-bpf programs ## cgroup-bpf Vast majority of twagent tasks have one or more cgroup-bpf features enabled: • mostly networking: ☐ IP assignment but not only: - sysctl access control Let's look at some of them ... ## Example of cgroup-bpf programs (bpftool cgroup tree): ![Image](/uploads/documents/1/4/a/7/14a78f1665ead57299ddbea78431f846/p3_1

## Debugging the BPF Virtual Machine eBPF Summit ## Why? ● Debugging is useful to understand how things work ● Sometimes, eBPF programs can’t even load - I couldn’t find good resources on this, so so, here I am ● I break lots of eBPF programs - The BPF Virtual machine is not easy to understand ## The approach ## The BPF subsystem lives in the kernel  target remote localhost:1234 (gdb) bpf/syscall.c:4180 (gdb) bpf/syscall.c:796 (gdb) b bpf/syscall.c:121 (gdb) b kernel/bpf/ringbuf.c:159 ## Remember to: - Load the eBPF program

to ship BPF with your Go project Lorenz Bauer eBPF Summit ## Goal • Count the number of packets on lo • Print the count to the console • From a single Go binary #### github.com/lmb/ship-bpf-with-go

## Steering connections to sockets with BPF socket lookup hook Jakub Sitnicki, Cloudflare @jkbs0 @cloudflare eBPF Summit ## Who am I? - Software Engineer at Cloudflare Spectrum TCP/UDP reverse proxy proxy, Linux kernel, ... - Contributor to Linux kernel networking & BPF subsystems Goal Fun? ## We will need VM running Linux kernel 5.9+ bpftool 5.9+ libbpf headers ☐ kernel headers ## vm $ uname dispatch with BPF socket lookup packet metadata struct bpf_sk_lookup { __u32 family; __u32 protocol; __u32 remote_ip4; __u32 remote_port; __u32 local_ip4; __u32 local_port; /* ... */ }; BPF program

RedBPF eBPF Summit ## I n This Talk • Different “types” of BPF programs • Write BPF programs in Rust • Add new feature in RedBPF • Use BPF maps to make stateful decisions • Load the program and protect Engineer @ CCP Games • @aquarhead on GitHub, Twitter... • Rust (and Elixir) • Disclaimer: new to BPF & kernel networking, pardon my mistake and welcome corrections! ## Sad Rabbit Has No Memory • - But adding such a feature in RabbitMQ could be a long process... ## Build a Limiter in BPF • Let's use BPF to get a quick win! • Track how many “AMQP consumers” have been declared for each connection

## 对 Go 程序进行可靠的性能测试 Changkun Ou https://changkun.de/s/gobench/ Go 夜读系列 | talkgo.org | Talk Go | 第 83 期 March 26, 2020  +0.89% DeleteCollision/*sync_Map-8 94.2ns ± 2% 5.7ns ± 2% -93.98% 2020 © Changkun Ou · Go 夜读 · 对 Go 程序进行可靠的性能测试 优化 src/sync/map.go 275 -delete(m.dirty, key) 275 +e, ok = m.dirty[key] 276 +m.missLocked() 当对数据的假设减少时，结论的不确定性就会增大，因此 p 值会相应的变大，进而使性能基准测试的条件更加严格。 ## 局限与应对措施 ## 降低系统噪音: perflock 作用是限制 CPU 时钟频率，从而一定程度上消除系统对性能测试程序的影响，减少结果的噪声，进而性能测量的结果方差更小也更加可靠，仅支持 Linux。 $ go get github.com/aclements/perflock/cmd/perflock $ sudo

开发框架介绍和最佳实践 基于 Vue.js 的小程序开发  ## 胡成全 @美团点评 美团酒旅 - 终端研发组 - 基础服务平台 动态化技术方向，小程序应用、RN 应用 努力于小程序工程化开发、业务级应用 ## 目录 mpvue mpvue 介绍 CONTENTS 使用方式 设计思路 实践 & 展望 ## mpvue 介绍 作为小程序应用开发框架，mpvue 具有什么特点？为开发者 带来了是什么？当前社区的反馈如何？ ## mpvue 是什么 使用 Vue.js 开发小程序的前端框架  Vue.js 代码  小程序代码 ## mpvue 的能力 Vue 编码规范 Vue 语法支持 开发规范扩展 Vue 组件机制 Vue 引擎驱动 cli 命令行工具 编译构建集成 工程化体系集成 npm 管理支持

天津商业大学信息工程学院 # PHP 语言程序设计 实验指导书（v1） 杨亮 2015年3月1日 ## 目录 实验 1：HTML 的基本使用 ..... 2 实验 2：CSS 与 JavaScript 的基本使用 ..... 3 实验 3：PHP 变量、控制结构与函数 ..... 4 实验 4：表单与 PHP 输入输出 ..... 5 实验 5：命令行下使用 MySQL