Rud Merriam | A Journey into Non-Virtual Polymorphism 2 Who Doesn’t Recognize This?? 1990 Borland Turbo C++Cppcon 2023 | Rud Merriam | A Journey into Non-Virtual Polymorphism 3 Background ● Experience – Medium.com (https://medium.com/@rudmerriam)Cppcon 2023 | Rud Merriam | A Journey into Non-Virtual Polymorphism 4 Polymorphism ● Greek: “many forms” (Obligatory statement) ● The use of a single variableCppcon 2023 | Rud Merriam | A Journey into Non-Virtual Polymorphism 5 Polymorphic Variables ● Base class pointer to derived class – Virtual functions are not bad! ● Standard Template Library

carePhoto by Tech Nick on unsplashSimple benchmark class Base { public: int concrete() const; virtual int virt() const; }; void benchmark(Base *b, size_t num_iterations) { auto start = Clock::now(); virt_duration = end-start;There are interesting technical details and surprising conclusions that virtual functions can be actually faster. Since CPU architectures are mentioned, I'd expect to see deep nt-vs-inheritance-vs-other- ways-performanceDoes it even matter?Conclusions ● The notion that “virtual functions are slower” is flat out wrong. ○ Which is not to say they are faster ○ Some of the suggested

Go runtime related problems in TiDB production environment About me ● Arthur Mao(毛康力), Senior Engineer@PingCAP ● TiDB core developer (top3 contributor) ● GitBook about golang internals (@tiancaiamao) Memory ● OS ○ Virtual memory ■ each process has its virtual address space ○ Physical memory ■ OS divides physical memory into pages ○ memory mapping ■ page fault, built the virtual-physical mapping talking about when we talk about Memory ● TLB (translation lookaside buffer) ○ A CPU cache for virtual memory to physical addresses mapping ○ Size limited, when cache miss the memory access become slower

name, const NodeConfig& config) : SyncActionNode(name, config) {} // You must override this virtual function NodeStatus tick() override { std::cout << "Type: [ApproachEnemy]. Instance:" <<

. . 20 1.4.2 Authenticating at web service logon . . . . . . . . . . . . . . . . . . . . 21 2 Environment-specific notes 23 2.1 Using the object-oriented web service (OOWS) . . . . . . . . . . . . . . Changing machine settings. Sessions . . . . . . . . . . . . . . . . . . . . . . . . 39 3.3 Launching virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 3.4 VirtualBox events . . . . . . . . . . . . . . . . . . . . 314 15 Contents 7 Host-Guest Communication Manager 315 7.1 Virtual hardware implementation . . . . . . . . . . . . . . . . . . . . . . . . . . 315 7.2 Protocol specification

. . 22 1.4.2 Authenticating at web service logon . . . . . . . . . . . . . . . . . . . . 23 2 Environment-specific notes 25 2.1 Using the object-oriented web service (OOWS) . . . . . . . . . . . . . . Changing machine settings. Sessions . . . . . . . . . . . . . . . . . . . . . . . . 45 3.3 Launching virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 3.4 VirtualBox events . . . . . . . . . . . . . . . . . . . . . . . . . . 350 7 Host-Guest Communication Manager 351 7.1 Virtual hardware implementation . . . . . . . . . . . . . . . . . . . . . . . . . . 351 7.2 Protocol specification

. . 22 1.4.2 Authenticating at web service logon . . . . . . . . . . . . . . . . . . . . 23 2 Environment-specific notes 25 2.1 Using the object-oriented web service (OOWS) . . . . . . . . . . . . . . Changing machine settings. Sessions . . . . . . . . . . . . . . . . . . . . . . . . 45 3.3 Launching virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 3.4 VirtualBox events . . . . . . . . . . . . . . . . . . . . . . . . . . 350 7 Host-Guest Communication Manager 351 7.1 Virtual hardware implementation . . . . . . . . . . . . . . . . . . . . . . . . . . 351 7.2 Protocol specification

. . 24 1.4.2 Authenticating at web service logon . . . . . . . . . . . . . . . . . . . . 25 2 Environment-specific notes 27 2.1 Using the object-oriented web service (OOWS) . . . . . . . . . . . . . . Changing machine settings: Sessions . . . . . . . . . . . . . . . . . . . . . . . . 47 3.3 Launching virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 3.4 VirtualBox events . . . . . . . . . . . . . . . . . . . . 390 19 Contents 7 Host-Guest Communication Manager 391 7.1 Virtual hardware implementation . . . . . . . . . . . . . . . . . . . . . . . . . . 391 7.2 Protocol specification

. . 24 1.4.2 Authenticating at web service logon . . . . . . . . . . . . . . . . . . . . 25 2 Environment-specific notes 27 2.1 Using the object-oriented web service (OOWS) . . . . . . . . . . . . . . Changing machine settings: Sessions . . . . . . . . . . . . . . . . . . . . . . . . 47 3.3 Launching virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 3.4 VirtualBox events . . . . . . . . . . . . . . . . . . . . . . . . . . 389 7 Host-Guest Communication Manager 390 7.1 Virtual hardware implementation . . . . . . . . . . . . . . . . . . . . . . . . . . 390 7.2 Protocol specification

. . 19 1.4.2 Authenticating at web service logon . . . . . . . . . . . . . . . . . . . . 20 2 Environment-specific notes 22 2.1 Using the object-oriented web service (OOWS) . . . . . . . . . . . . . . Changing machine settings. Sessions . . . . . . . . . . . . . . . . . . . . . . . . 39 3.3 Launching virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 3.4 VirtualBox events . . . . . . . . . . . . . . . . . . . . . . . . . . 284 7 Host-Guest Communication Manager 285 7.1 Virtual hardware implementation . . . . . . . . . . . . . . . . . . . . . . . . . . 285 7.2 Protocol specification