# SANS-I/O runtime (Working in progress) (This module is in very early stage of development. It is not ready for production use.) This is a simple, lightweight, and fast runtime for the SansIo mechanism. ## Goal The goal of this project is to provide a simple, lightweight, and fast runtime for the SansIo mechanism. The runtime should be able to run on any platform with variables network library like: mio, io_uring, af_xdp. ## How it works Controller will spawn some threads and each thread will run a worker. The workers ## Features | Impl | C/I | Works | Benchmark | Group | Description | | ---- | --- | ----- | --------- | ------- | ---------------------------------- | | [x] | [ ] | [x] | [ ] | Control | Cross tasks communication | | [x] | [ ] | [x] | [x] | Control | Controller to worker communication | | [x] | [ ] | [x] | [ ] | Control | Controller to task communication | | [x] | [ ] | [x] | [ ] | Control | Workers status monitoring | | [x] | [ ] | [x] | [ ] | I/O | Udp | | [x] | [ ] | [x] | [ ] | I/O | Tun/Tap | | [ ] | [ ] | [ ] | [ ] | I/O | Tcp | | [ ] | [ ] | [ ] | [ ] | I/O | Rpc | | [x] | [ ] | [x] | [ ] | Backend | mio | | [x] | [ ] | [x] | [ ] | Backend | raw poll | | [x] | [ ] | [x] | [ ] | Backend | polling | | [ ] | [ ] | [ ] | [ ] | Backend | io_uring | | [ ] | [ ] | [ ] | [ ] | Backend | af_xdp | | [x] | [ ] | [x] | [ ] | Example | Udp echo server | | [x] | [ ] | [x] | [ ] | Example | Udp echo client | | [x] | [ ] | [x] | [ ] | Example | Simple Whip/Whep server | ## [Benchmarking](./docs/benchmark.md) - External communication can archive 1.5M messages (1500 bytes) per second, that is 1.5M * 1500 * 8 = 18Gbps, this is just enough for almost of application. The latency is 2.5ms, because of we doing in polling base, maybe it can improve by using interrupt base. ## Design  ### Single task Bellow is state diagram of a single task. ```mermaid stateDiagram [*] --> Created Created --> Waiting : attach to worker Waiting --> OnTick : timer fired OnTick --> Waiting : no output OnTick --> PopOutput : has output PopOutput --> PopOutput : has output PopOutput --> Waiting : no output Waiting --> OnInput : I/O, Bus OnInput --> Waiting : no output OnInput --> PopOutput : has output ``` The idea is in SAN/IO style, each task will reduce memory by create output immediately after input. We need to pop the output before we can receive the next input. ### Multi tasks With idea of SAN/IO is we need to pop the output before we can receive the next input. This is a problem when we have multiple tasks. We need to have a way to control the order of the tasks. ```mermaid stateDiagram [*] --> Created Created --> Waiting : attach groups to worker Waiting --> OnTick : timer fired OnTick --> OnTickSingleTask : next task OnTick --> Waiting : no task OnTickSingleTask --> OnTick : no output OnTickSingleTask --> PopCurrentTickTaskOutput : has output PopCurrentTickTaskOutput --> PopCurrentTickTaskOutput : has output PopCurrentTickTaskOutput --> OnTick : no output Waiting --> OnInput : I/O, Bus OnInput --> OnInputSingleTask : has task OnInputSingleTask --> Waiting : no output OnInputSingleTask --> PopCurrentInputTaskOutput : has output PopCurrentInputTaskOutput --> PopCurrentInputTaskOutput : has output PopCurrentInputTaskOutput --> Waiting : no output ```