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denoland-deno/core/examples/hello_world.rs
Aapo Alasuutari 2164f6b1eb
perf(ops): Monomorphic sync op calls (#15337)
Welcome to better optimised op calls! Currently opSync is called with parameters of every type and count. This most definitely makes the call megamorphic. Additionally, it seems that spread params leads to V8 not being able to optimise the calls quite as well (apparently Fast Calls cannot be used with spread params).

Monomorphising op calls should lead to some improved performance. Now that unwrapping of sync ops results is done on Rust side, this is pretty simple:

```
opSync("op_foo", param1, param2);
// -> turns to
ops.op_foo(param1, param2);
```

This means sync op calls are now just directly calling the native binding function. When V8 Fast API Calls are enabled, this will enable those to be called on the optimised path.

Monomorphising async ops likely requires using callbacks and is left as an exercise to the reader.
2022-08-11 15:56:56 +02:00

68 lines
1.6 KiB
Rust

// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
//! This example shows you how to define ops in Rust and then call them from
//! JavaScript.
use deno_core::op;
use deno_core::Extension;
use deno_core::JsRuntime;
use deno_core::RuntimeOptions;
// This is a hack to make the `#[op]` macro work with
// deno_core examples.
// You can remove this:
use deno_core::*;
#[op]
fn op_sum(nums: Vec<f64>) -> Result<f64, deno_core::error::AnyError> {
// Sum inputs
let sum = nums.iter().fold(0.0, |a, v| a + v);
// return as a Result<f64, AnyError>
Ok(sum)
}
fn main() {
// Build a deno_core::Extension providing custom ops
let ext = Extension::builder()
.ops(vec![
// An op for summing an array of numbers
// The op-layer automatically deserializes inputs
// and serializes the returned Result & value
op_sum::decl(),
])
.build();
// Initialize a runtime instance
let mut runtime = JsRuntime::new(RuntimeOptions {
extensions: vec![ext],
..Default::default()
});
// Now we see how to invoke the op we just defined. The runtime automatically
// contains a Deno.core object with several functions for interacting with it.
// You can find its definition in core.js.
runtime
.execute_script(
"<usage>",
r#"
// Print helper function, calling Deno.core.print()
function print(value) {
Deno.core.print(value.toString()+"\n");
}
const arr = [1, 2, 3];
print("The sum of");
print(arr);
print("is");
print(Deno.core.ops.op_sum(arr));
// And incorrect usage
try {
print(Deno.core.ops.op_sum(0));
} catch(e) {
print('Exception:');
print(e);
}
"#,
)
.unwrap();
}