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perf: Change ImageWorker from round robin to load based #723

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perf: Change ImageWorker from round robin to load based #723

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47 changes: 36 additions & 11 deletions src/core/lib/ImageWorker.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -178,7 +178,7 @@ export class ImageWorkerManager {
imageWorkersEnabled = true;
messageManager: Record<number, MessageCallback> = {};
workers: Worker[] = [];
workerIndex = 0;
workerLoad: number[] = [];
nextId = 0;

constructor(
Expand All @@ -189,14 +189,19 @@ export class ImageWorkerManager {
numImageWorkers,
createImageBitmapSupport,
);
this.workers.forEach((worker) => {
worker.onmessage = this.handleMessage.bind(this);
this.workers.forEach((worker, index) => {
worker.onmessage = (event) => this.handleMessage(event, index);
});
}

private handleMessage(event: MessageEvent) {
private handleMessage(event: MessageEvent, workerIndex: number) {
const { id, data, error } = event.data as ImageWorkerMessage;
const msg = this.messageManager[id];

if (this.workerLoad[workerIndex]) {
this.workerLoad[workerIndex]--;
}

if (msg) {
const [resolve, reject] = msg;
delete this.messageManager[id];
Expand Down Expand Up @@ -242,14 +247,30 @@ export class ImageWorkerManager {
const workers: Worker[] = [];
for (let i = 0; i < numWorkers; i++) {
workers.push(new Worker(blobURL));
this.workerLoad.push(0);
}
return workers;
}

private getNextWorker(): Worker | undefined {
const worker = this.workers[this.workerIndex];
this.workerIndex = (this.workerIndex + 1) % this.workers.length;
return worker;
private getNextWorkerIndex(): number {
if (this.workers.length === 0) return -1;

let minLoad = 99;
let workerIndex = 0;

for (let i = 0; i < this.workers.length; i++) {
const load = this.workerLoad[i] || 0;

if (load === 0) {
return i;
}

if (load < minLoad) {
minLoad = load;
workerIndex = i;
}
}
return workerIndex;
}

getImage(
Expand All @@ -265,9 +286,13 @@ export class ImageWorkerManager {
if (this.workers) {
const id = this.nextId++;
this.messageManager[id] = [resolve, reject];
const nextWorker = this.getNextWorker();
if (nextWorker) {
nextWorker.postMessage({
const nextWorkerIndex = this.getNextWorkerIndex();

if (nextWorkerIndex !== -1) {
const worker = this.workers[nextWorkerIndex];
// eslint-disable-next-line @typescript-eslint/no-non-null-assertion
this.workerLoad[nextWorkerIndex]!++;
worker!.postMessage({
id,
src: src,
premultiplyAlpha,
Expand Down