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[node] Switch to setImmediate to avoid starving the Node.js event loop (
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#19610)

### Description
<!-- Describe your changes. -->
Switch to setImmediate to avoid starving the Node.js event loop

There should really be a true async version though, running
computationally intensive things on the event loop will stop everything
else from happening while it is running, e.g. a web server from
answering requests.

This can be done by wrapping `RunAsync` behind a
[`napi::Promise`](https://github.com/nodejs/node-addon-api/blob/main/doc/promises.md)
to run on the onnxruntime thread pool or [`AsyncWorker`](
https://github.com/nodejs/node-addon-api/blob/main/doc/async_worker.md)
for the Node.js/libuv thread pool.

### Motivation and Context
<!-- - Why is this change required? What problem does it solve?
- If it fixes an open issue, please link to the issue here. -->
Without this, if you run inference in a tight loop, without anything
else in between that is async/deferred, `process.nextTick` will lead to
starving the event loop and not letting anything else run,
`setImmediate` at least lets the event loop spin between calls to `run`.

See
https://dev.to/ynmanware/setimmediate-settimeout-and-process-nexttick-3mfd

Contributed on behalf of [Swimm](https://swimm.io/)
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segevfiner authored Feb 23, 2024
1 parent 4ab4976 commit 29b1106
Showing 1 changed file with 2 additions and 2 deletions.
4 changes: 2 additions & 2 deletions js/node/lib/backend.ts
Original file line number Diff line number Diff line change
Expand Up @@ -36,7 +36,7 @@ class OnnxruntimeSessionHandler implements InferenceSessionHandler {
async run(feeds: SessionHandler.FeedsType, fetches: SessionHandler.FetchesType, options: InferenceSession.RunOptions):
Promise<SessionHandler.ReturnType> {
return new Promise((resolve, reject) => {
process.nextTick(() => {
setImmediate(() => {
try {
resolve(this.#inferenceSession.run(feeds, fetches, options));
} catch (e) {
Expand All @@ -56,7 +56,7 @@ class OnnxruntimeBackend implements Backend {
async createInferenceSessionHandler(pathOrBuffer: string|Uint8Array, options?: InferenceSession.SessionOptions):
Promise<InferenceSessionHandler> {
return new Promise((resolve, reject) => {
process.nextTick(() => {
setImmediate(() => {
try {
resolve(new OnnxruntimeSessionHandler(pathOrBuffer, options || {}));
} catch (e) {
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