From 29b1106033e291947debb49c3fd03feb479c4b1b Mon Sep 17 00:00:00 2001
From: Segev Finer <segev208@gmail.com>
Date: Fri, 23 Feb 2024 04:53:50 +0200
Subject: [PATCH] [node] Switch to setImmediate to avoid starving the Node.js
 event loop (#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/)
---
 js/node/lib/backend.ts | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/js/node/lib/backend.ts b/js/node/lib/backend.ts
index e8eb0e9babf5a..927953b4f1dd6 100644
--- a/js/node/lib/backend.ts
+++ b/js/node/lib/backend.ts
@@ -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) {
@@ -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) {