multi-threaded-parallel

Call a Wasm Library from Host

This example demonstrates how to use WasmEdge Rust SDK to create multiple threads to help us render Mandelbrot set in parallel, which is a compute-intensive workload. This example also present sharing the image memory between threads while rendering the image parallelly.

This example consists of three parts:

• mandelbrot-c contains mandelbrot.c that defines a C library of mandelbrot.

• run-mandelbrot-in-parallel is a host application that loads the wasm binary generated from wasm-lib, and runs the wasm function exported by the wasm library over WasmEdge Runtime.

• visualize_result.ipynb is a Python notebook file that visualizes the generated image file.

Now let's build and run this example.

• Install rustup and Rust

  Go to the official Rust webpage and follow the instructions to install rustup and Rust.

  It is recommended to use Rust 1.71 or above in the stable channel.

  Then, add wasm32-wasi target to the Rustup toolchain:

  rustup target add wasm32-wasi

• Install WasmEdge Runtime

  Refer to the Quick Install section of WasmEdge Runtime Book to install WasmEdge Runtime. Or, use the following command directly

  # NOTICE that the installation script needs `sudo` access
  
  # install wasmedge to the directory /usr/local/
  curl -sSf https://raw.githubusercontent.com/WasmEdge/WasmEdge/master/utils/install.sh | bash -s -- -v 0.13.5 -p /usr/local

  For users in China mainland (中国大陆地区), try the following command to install WasmEdge Runtime if failed to run the command above

  # NOTICE that the installation script needs `sudo` access
  
  bash install_zh.sh -v 0.13.5 -p /usr/local

• Install zig

  Go to the Install Zig from a Package Manager and follow the instructions to install zig. With Zig, you will not need to separately install the WASI SDK, as it is included with the toolchain.

• Download example

  git clone [email protected]:second-state/wasmedge-rustsdk-examples.git
  cd wasmedge-rustsdk-examples/multi-threaded-parallel

• Compile mandelbrot-c into mandelbrot.wasm

  cd mandelbrot-c
  
  # compile mandelbrot.c to mandelbrot.o
  zig build-obj -O ReleaseSmall -target wasm32-wasi mandelbrot.c
  
  # link mandelbrot.o to mandelbrot.wasm
  wasm-ld --no-entry mandelbrot.o -o mandelbrot.wasm --import-memory --export-all --shared-memory --features=mutable-globals,atomics,bulk-memory
  
  # go back to the root directory of `multi-threaded-parallel`
  cd ..

  If wasm-ld command is not found, use the command dpkg -L lld-12 | grep wasm-ld to check if it is installed along with llvm.

  If the commands run successfully, mandelbrot.wasm can be found in the directory of mandelbrot-c.

• Build and run run-mandelbrot-in-parallel

  # in wasmedge-rust-examples/multi-threaded-parallel
  cargo run -p run-mandelbrot-in-parallel -- ./mandelbrot-c/mandelbrot.wasm

  If the command runs successfully, then the following message is printed out on the screen:

  [2022-12-19 00:04:33.249] [info] compile start
  [2022-12-19 00:04:33.257] [info] verify start
  [2022-12-19 00:04:33.257] [info] optimize start
  [2022-12-19 00:04:33.280] [info] codegen start
  [2022-12-19 00:04:33.296] [info] output start
  [2022-12-19 00:04:33.311] [info] compile done
  Time elapsed: 486.07ms

  In addition, the command above generates two files: one is the image file mandelbrot-image.bin, one is a AOT file.

• Visualize the generated image file

  Open the notebook file visualize_result.ipynb and follow the instructions to visualize the generated image file.