Struct GuestProfilerModules 

pub struct GuestProfilerModules { /* private fields */ }

Available on crate features profiling and runtime only.

The set of modules a GuestProfiler attributes samples to, prepared once and shared by any number of profilers.

Preparing a module builds its symbol table, which demangles the name of every function it defines; for modules with many functions this is the bulk of the cost of starting a profile. GuestProfiler::new does this work every time it is called. Embedders that profile the same modules repeatedly, for example once per request or once per instance, can instead build a GuestProfilerModules once and pass it to GuestProfiler::new_with_modules for each profile, which then does no per-module work beyond registering the prepared symbol tables.

Cloning is cheap, since the prepared modules are reference-counted, and a GuestProfilerModules can be shared between threads. Profiles started from the same set are independent of one another.

Example

let engine = Engine::default();
let module = Module::new(&engine, r#"(module (func (export "run")))"#)?;

// Prepare the modules once...
let modules = GuestProfilerModules::new(&engine, [("main.wasm".to_string(), module.clone())])?;

// ...then start a profile for each guest that runs them.
for _ in 0..3 {
    let profiler = GuestProfiler::new_with_modules("main", Duration::from_millis(10), &modules);
    let mut store = Store::new(&engine, profiler);
    // Arrange to call `GuestProfiler::sample` while the guest runs, for
    // example from `Store::epoch_deadline_callback`.
    let instance = Instance::new(&mut store, &module, &[])?;
    instance
        .get_typed_func::<(), ()>(&mut store, "run")?
        .call(&mut store, ())?;
    let mut profile = Vec::new();
    store.into_data().finish(&mut profile)?;
}

Implementations

impl GuestProfilerModules

pub fn new( engine: &Engine, modules: impl IntoIterator<Item = (String, Module)>, ) -> Result<Self>

Prepares modules for profiling.

Each entry pairs a module with the name it is given in profiles. Only modules in modules appear in stack traces of profiles that use this set; stack frames executing host code or functions from other modules are omitted. See the “Security” section of the GuestProfiler documentation for guidance on which modules to include. Modules that define no functions are skipped, since no sample can land in them.

Errors

Returns an error if engine has guest debugging enabled, which profiling does not support.

Panics

Panics if any module in modules was not created with engine.

pub fn new_component( engine: &Engine, component: &Component, extra_modules: impl IntoIterator<Item = (String, Module)>, ) -> Result<Self>

Available on crate feature component-model only.

Prepares the static modules of component, plus extra_modules, for profiling.

See GuestProfilerModules::new for additional information.

Trait Implementations

impl Clone for GuestProfilerModules

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for GuestProfilerModules

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.