Debugging the BPF Virtual Machine Lorenzo Fontana October 28, 2020 ● Debugging is useful to understand how things work ● Sometimes, eBPF programs can’t even load ● I couldn’t find good resources on this this, so, here I am ● I break lots of eBPF programs ● The BPF Virtual machine is not easy to understand Why ? The BPF subsystem lives in the kernel AND The kernel can be debugged using gdb The

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

Hierarchical State Machines The graphical representation of the nodes in a BT has a meaning. Children are ordered from left to right.Are Behavior Trees better than Hierarchical State Machines? HSM BT BT.CPPState CPPState Machines Behavior Trees Learning curve more familiar it needs some practice Concurrency no yes Scalability poor better Readability scales very poorly better Behavior Trees VS Hierarchical Hierarchical State Machines"Tick" and Node types ● The “tick” is the signal that we propagate from the root to the leaves. ● The leaves of the tree are the Actions. I.e. the user-defined code that should be

#IstioCon Is Your Virtual Machine Really Ready-to-go with Istio? Kailun Qin, Intel Haoyuan Ge #IstioCon Quick Summary (from Google Cloud Next ’19 [1]) VM works on Istio! [1] Istio Service Mesh Hybrid and Multi Clouds #IstioCon Istio VM Integration is? A Tumultuous Odyssey… [1] Istio 1.8: A Virtual Machine Integration Odyssey, Jimmy Song #IstioCon V0.2 Mesh Expansion ● Prerequisites ○ IP connectivity the workloads themselves #IstioCon V1.6-1.8 Better VM Workload Abstraction Item Kubernetes Virtual Machine Basic schedule unit Pod WorkloadEntry Component Deployment WorkloadGroup Service registry

#IstioCon Building resilient systems inside the mesh: abstraction and automation of Virtual Service generation Vladimir Georgiev, Thought Machine #IstioCon Sync calls failures inside the mesh implement this to be language agnostic? #IstioCon Virtual Services API ● Solves our problems, but… ● All Service Owners must be aware of the Virtual Services API in order to define their SLOs. ● Potential errors when dealing with YAMLs. ● Potential drift between the state of the service API and the Virtual Service config. ● Hard to manage when having hundreds of services. #IstioCon Abstracting to proto

. . . . . . . . . . . . 16 1.7 Creating your first virtual machine . . . . . . . . . . . . . . . . . . . . . . . . . 17 1.8 Running your virtual machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 1.11 Virtual machine configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 1.12 Removing virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 1.13 Cloning virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 1.14 Importing and exporting virtual machines . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . 16 1.7 Creating your first virtual machine . . . . . . . . . . . . . . . . . . . . . . . . . 17 1.8 Running your virtual machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 1.11 Virtual machine configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 1.12 Removing virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 1.13 Cloning virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 1.14 Importing and exporting virtual machines . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . 16 1.7 Creating your first virtual machine . . . . . . . . . . . . . . . . . . . . . . . . . 17 1.8 Running your virtual machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 1.11 Virtual machine configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 1.12 Removing virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 1.13 Cloning virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 1.14 Importing and exporting virtual machines . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . 16 1.7 Creating your first virtual machine . . . . . . . . . . . . . . . . . . . . . . . . . 17 1.8 Running your virtual machine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 1.10 Virtual machine configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 1.11 Removing virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 1.12 Cloning virtual machines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 1.13 Importing and exporting virtual machines . . . . . . . . . . . . . . . . . .