fix(ootk-multi): improved multithreading algorithm to reduce garbage …

…collection and variable cloning
thkruz · Jan 16, 2021 · f9e5d63 · f9e5d63
1 parent 774ec62
commit f9e5d63
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Showing 4 changed files with 49 additions and 19 deletions.
diff --git a/package.json b/package.json
@@ -9,6 +9,7 @@
     "lint": "eslint src",
     "lint:fix": "eslint src --fix",
     "lint:test": "eslint test",
+    "sandbox": "http-server ./",
     "test": "jest -c scripts/jest-std.json",
     "test:coverage": "jest --coverage -c scripts/jest-std.json",
     "test:performance": "node test/performance/timing.test.mjs",

diff --git a/sandbox.html b/sandbox.html
@@ -1,12 +1,8 @@
 <html>
   <head>
     <script src="./dist/ootk.js"></script>
-    <script>
-      var line1 = "1 00005U 58002B   00179.78495062  .00000023  00000-0  00098-0 0  4753";
-      var line2 ="2 00005  34.2682 348.7242 1859667 331.7664  19.3264 10.82419157413667";
-      var satrec = Ootk.Sgp4.createSatrec(line1, line2, "wgs72", "i");
-      var multi = new Ootk.Multi(8);
-      multi.propagate([satrec], [0,1,2,3,4,5,6,7,8,9,10]).then((m) => console.log(m))
-    </script>
+    <script src="./test/performance/satellite.js"></script>
+    <script src="./test/performance/performance.js"></script>
   </head>
+  <body></body>
 </html>
diff --git a/src/ootk-multi.ts b/src/ootk-multi.ts
@@ -153,8 +153,12 @@ interface SatelliteRecord {
 class Multi {
   threads = 0;
   thread = [];
+  encoderInst = null;
+  decoderInst = null;
 
   constructor(threads: number) {
+    this.encoderInst = new TextEncoder();
+    this.decoderInst = new TextDecoder();
     this.threads = threads;
     for (let index = 0; index < this.threads; index++) {
       this.thread[index] = new Worker('./dist/ootk-multi.worker.js');
@@ -163,32 +167,35 @@ class Multi {
 
   public propagate(satrecs: SatelliteRecord[], times: number[]) {
     return this._propagate(satrecs, times).then((results) => {
-      let returnArray = [];
+      const returnArray = new Float32Array(satrecs.length * times.length * 7);
+      let offset = 0;
       for (let index = 0; index < this.threads; index++) {
-        returnArray = returnArray.concat(JSON.parse(results[index].data));
+        const dataArray = new Float32Array(results[index].data);
+        returnArray.set(dataArray,offset);
+        offset += dataArray.length;
       }
       return returnArray;
     });
   }
 
   private async _propagate(satrecs: SatelliteRecord[], times: number[]): Promise<any> {
-    const tasks = Multi.chunkArray(satrecs, this.threads);
+    const tasks = Multi.chunkArray2(satrecs, this.threads);
     const results = [];
 
     for (let index = 0; index < this.threads; index++) {
       const whichWorker = this.thread[index];
-      const task = JSON.stringify({ type: 'propagate', tasks: tasks[index], times: times });
-      results.push(this.createTasks(whichWorker, task));
+      const taskBuffer = this.encoderInst.encode(JSON.stringify({ type: 'propagate', tasks: tasks[index], times: times })).buffer;
+      results.push(this.createTasks(whichWorker, taskBuffer));
     }
 
     return Promise.all(results).then((data) => data);
   }
 
   // eslint-disable-next-line class-methods-use-this
-  private createTasks(whichWorker: Worker, task: string): Promise<any> {
+  private createTasks(whichWorker: Worker, taskBuffer): Promise<any> {
     return new Promise((resolve, reject) => {
-      whichWorker.postMessage(task);
-      whichWorker.onmessage = (m) => {
+      whichWorker.postMessage(taskBuffer,[taskBuffer]);
+      whichWorker.onmessage = (m) => {        
         resolve(m);
         // whichWorker.terminate();
       };
@@ -199,6 +206,19 @@ class Multi {
     });
   }
 
+  private static chunkArray2(sourceArr: SatelliteRecord[], chunks: number): SatelliteRecord[][] {
+    const lengthOfArray = sourceArr.length;
+    const chunkSize = Math.floor(lengthOfArray / chunks);
+    const result = [];
+
+    let i = 0;
+    while (i < lengthOfArray) {
+      result.push(sourceArr.slice(i, (i += chunkSize)));
+    }
+
+    return result;
+  }
+
   private static chunkArray(sourceArr: SatelliteRecord[], chunks: number): SatelliteRecord[][] {
     const lengthOfArray = sourceArr.length;
     const result = Array.from(Array(chunks), () => []);

diff --git a/src/ootk-multi.worker.js b/src/ootk-multi.worker.js
@@ -1,8 +1,11 @@
 // eslint-disable-next-line no-undef
 importScripts('./ootk-sgp4.js');
 
+const decoderInst = new TextDecoder();
+const encoderInst = new TextEncoder();
+
 onmessage = function (m) {
-  const data = JSON.parse(m.data);
+  const data = JSON.parse(decoderInst.decode(m.data));
   switch (data.type) {
     case 'propagate':
       propagate(data);
@@ -23,9 +26,19 @@ var propagate = (data) => {
     for (let j = 0; j < times.length; j++) {
       // eslint-disable-next-line no-undef
       const stateVector = Ootk.Sgp4.propagate(satrecs[i], times[j]);
-      satResults.push({ t: times[j], sv: stateVector });
+      satResults.push(
+        times[j],
+        stateVector.position.x,
+        stateVector.position.y,
+        stateVector.position.z,
+        stateVector.velocity.x,
+        stateVector.velocity.y,
+        stateVector.velocity.z,
+      );
     }
-    allResults.push(satResults);
+    allResults.push(...satResults);
   }
-  postMessage(JSON.stringify(allResults));
+
+  const resultBuffer = new Float32Array(allResults).buffer;
+  postMessage(resultBuffer, [resultBuffer]);
 };