In-Network Computing Simulator for Parallel Programming

This program is designed to simulate a parallel computing system based on fat-tree topology with in-network computing capability.

What is in-network computing?

An in-network computing capable system can perform tasks within the network infrastructure, rather than exclusively at the endpoints.

Why do we need it?

There are a couple of reasons behind this concept. 1. Reduced Latency: By processing data within the network, in-network computing can significantly reduce latency. This is because data does not need to travel back and forth between endpoints for processing. 2. Bandwidth Efficiency: It can optimize bandwidth usage by processing data locally, reducing the amount of data that needs to be transmitted across the network. 3. Energy Efficiency: By reducing the need for data to traverse long distances to centralized data centers, in-network computing can lead to energy savings, making it a more sustainable solution for large-scale data processing.

Usage

Writing and building a custom parallel application within the simulator is described in this section. For now, it only supports Linux.

Dependencies

The only external dependency of the program is spdlog v1.15.0 library which is used for logging events in the program.

Bash git clone --branch v1.15.0 https://github.com/gabime/spdlog.git && mkdir -p spdlog/build && cd spdlog/build && cmake -DSPDLOG_BUILD_SHARED=ON -DSPDLOG_ENABLE_PCH=ON -DSPDLOG_BUILD_EXAMPLE=OFF -DSPDLOG_INSTALL=ON -DSPDLOG_USE_STD_FORMAT=OFF .. && make -j all && sudo make install

Implementing Custom Parallel Applications

The program is designed to ease migrations from traditional MPI-based programs. So, the programming interface is quite similar to that. Just like you were writing a program using the MPI library, you need to write a program in the Computer::task(..) function.

Example Program

Below is an example program in which node #7 sends an array to node #12.

```C++ void Computer::task() { spdlog::trace("Computer({}): Task started..", m_ID);

if(7 == m_ID) {
    std::vector<float> data({1.0f, 2.0f, 3.0f, 4.0f, 5.0f});

    m_mpi.send(data, 12);
}
else if(12 == m_ID) {
    std::vector<float> data;
    m_mpi.receive(data, 7);

    spdlog::info("Computer({}): Received data from Computer(7):", m_ID);
    for(const auto &d : data) {
        spdlog::info("{}", d);
    }
}
else {
    // Do nothing
}

spdlog::warn("Computer({}): Task finished..", m_ID);
m_bDone = true;

} ```

And the output for the program is as below. Note that the order of task finished warnings might differ.

```shell InNetworkComputing: ./build/InNetworkComputing

[2024-05-25 14:42:14.912] [info] Starting program.. [2024-05-25 14:42:14.912] [info] Network established successfully! [2024-05-25 14:42:14.912] [warning] Computer(3): Task finished.. [2024-05-25 14:42:14.913] [warning] Computer(2): Task finished.. [2024-05-25 14:42:14.913] [warning] Computer(4): Task finished.. [2024-05-25 14:42:14.913] [warning] Computer(0): Task finished.. [2024-05-25 14:42:14.913] [warning] Computer(1): Task finished.. [2024-05-25 14:42:14.913] [warning] Computer(5): Task finished.. [2024-05-25 14:42:14.913] [warning] Computer(6): Task finished.. [2024-05-25 14:42:14.913] [warning] Computer(11): Task finished.. [2024-05-25 14:42:14.913] [warning] Computer(8): Task finished.. [2024-05-25 14:42:14.913] [warning] Computer(13): Task finished.. [2024-05-25 14:42:14.913] [warning] Computer(9): Task finished.. [2024-05-25 14:42:14.913] [warning] Computer(10): Task finished.. [2024-05-25 14:42:14.913] [warning] Computer(14): Task finished.. [2024-05-25 14:42:14.913] [warning] Computer(15): Task finished.. [2024-05-25 14:42:14.914] [info] Computer(12): Received data from Computer(7): [2024-05-25 14:42:14.914] [info] 1 [2024-05-25 14:42:14.914] [info] 2 [2024-05-25 14:42:14.914] [info] 3 [2024-05-25 14:42:14.914] [info] 4 [2024-05-25 14:42:14.914] [info] 5 [2024-05-25 14:42:14.914] [warning] Computer(12): Task finished.. [2024-05-25 14:42:14.915] [warning] Computer(7): Task finished.. [2024-05-25 14:42:14.915] [info] All computing nodes have finished their tasks! [2024-05-25 14:42:14.915] [warning] Program finished after 129 ticks! ```

Design

Implementation