41594dc5d9
This commit exposes some various details and config options for having finer-grain control over mlock-ing the memory of modules. This amounts to three different changes being present in this commit: * A new `Module::image_range` API is added to expose the range in host memory of where the compiled image resides. This enables embedders to make mlock-ing decisions independently of Wasmtime. Otherwise though there's not too much useful that can be done with this range information at this time. * A new `Config::force_memory_init_memfd` option has been added. This option is used to force the usage of `memfd_create` on Linux even when the original module comes from a file on disk. With mlock-ing the main purpose for Wasmtime is likely to be avoiding major page faults that go back to disk, so this is another major source of avoiding page faults by ensuring that the initialization contents of memory are always in RAM. * The `memory_images` field of a `Module` has gone back to being lazily created on the first instantiation, effectively reverting #3914. This enables embedders to defer the creation of the image to as late as possible to allow modules to be created from precompiled images without actually loading all the contents of the data segments from disk immediately. These changes are all somewhat low-level controls which aren't intended to be generally used by embedders. If fine-grained control is desired though it's hoped that these knobs provide what's necessary to be achieved.
wasmtime
A standalone runtime for WebAssembly
A Bytecode Alliance project
Guide | Contributing | Website | Chat
Installation
The Wasmtime CLI can be installed on Linux and macOS with a small install script:
$ curl https://wasmtime.dev/install.sh -sSf | bash
Windows or otherwise interested users can download installers and binaries directly from the GitHub Releases page.
Example
If you've got the Rust compiler installed then you can take some Rust source code:
fn main() {
println!("Hello, world!");
}
and compile/run it with:
$ rustup target add wasm32-wasi
$ rustc hello.rs --target wasm32-wasi
$ wasmtime hello.wasm
Hello, world!
Features
-
Lightweight. Wasmtime is a standalone runtime for WebAssembly that scales with your needs. It fits on tiny chips as well as makes use of huge servers. Wasmtime can be embedded into almost any application too.
-
Fast. Wasmtime is built on the optimizing Cranelift code generator to quickly generate high-quality machine code at runtime.
-
Configurable. Whether you need to precompile your wasm ahead of time, or interpret it at runtime, Wasmtime has you covered for all your wasm-executing needs.
-
WASI. Wasmtime supports a rich set of APIs for interacting with the host environment through the WASI standard.
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Standards Compliant. Wasmtime passes the official WebAssembly test suite, implements the official C API of wasm, and implements future proposals to WebAssembly as well. Wasmtime developers are intimately engaged with the WebAssembly standards process all along the way too.
Language Support
You can use Wasmtime from a variety of different languages through embeddings of the implementation:
- Rust - the
wasmtimecrate - C - the
wasm.h,wasi.h, andwasmtime.hheaders or usewasmtimeConan package - C++ - the
wasmtime-cpprepository or usewasmtime-cppConan package - Python - the
wasmtimePyPI package - .NET - the
WasmtimeNuGet package - Go - the
wasmtime-gorepository
Documentation
📚 Read the Wasmtime guide here! 📚
The wasmtime guide is the best starting point to learn about what Wasmtime can do for you or help answer your questions about Wasmtime. If you're curious in contributing to Wasmtime, it can also help you do that!
It's Wasmtime.