pmndrs · jerzakm · Feb 10, 2026 · Feb 10, 2026 · Feb 10, 2026 · Feb 10, 2026
diff --git a/examples/apps/stress-test/index.html b/examples/apps/stress-test/index.html
@@ -0,0 +1,12 @@
+<!doctype html>
+<html lang="en">
+  <head>
+    <meta charset="UTF-8" />
+    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
+    <title>Koota ECS Stress Test</title>
+  </head>
+  <body>
+    <div id="app"></div>
+    <script type="module" src="/src/main.ts"></script>
+  </body>
+</html>
diff --git a/examples/apps/stress-test/package.json b/examples/apps/stress-test/package.json
@@ -0,0 +1,19 @@
+{
+  "name": "@app/stress-test",
+  "private": true,
+  "version": "0.0.1",
+  "type": "module",
+  "scripts": {
+    "dev": "vite --host",
+    "build": "tsc && vite build",
+    "preview": "vite preview"
+  },
+  "dependencies": {
+    "koota": "workspace:*",
+    "@sim/stress-test": "workspace:*"
+  },
+  "devDependencies": {
+    "@config/typescript": "workspace:*",
+    "vite": "catalog:"
+  }
+}
diff --git a/examples/apps/stress-test/src/main.ts b/examples/apps/stress-test/src/main.ts
@@ -0,0 +1,249 @@
+import type { BenchResult } from "@sim/stress-test";
+import {
+  benchMixedWorkload,
+  benchMultiQueryPopulation,
+  benchNotQueryChurn,
+  benchQueryIteration,
+  benchSpawnDestroy,
+  benchTraitChurn,
+  benchWideArchetype,
+} from "@sim/stress-test";
+
+const ITERATIONS = 50;
+
+type Suite = { name: string; run: () => BenchResult };
+
+const suites: Suite[] = [
+  { name: "spawn & destroy", run: () => benchSpawnDestroy(ITERATIONS) },
+  { name: "trait churn", run: () => benchTraitChurn(ITERATIONS) },
+  { name: "updateEach", run: () => benchQueryIteration(ITERATIONS) },
+  {
+    name: "multi-query population",
+    run: () => benchMultiQueryPopulation(ITERATIONS),
+  },
+  { name: "wide archetype", run: () => benchWideArchetype(ITERATIONS) },
+  { name: "not-query churn", run: () => benchNotQueryChurn(ITERATIONS) },
+  { name: "mixed workload", run: () => benchMixedWorkload(ITERATIONS) },
+];
+
+function fmtMs(v: number): string {
+  if (v < 0.001) return `${(v * 1000).toFixed(2)} µs`;
+  if (v < 1) return `${(v * 1000).toFixed(1)} µs`;
+  return `${v.toFixed(3)} ms`;
+}
+
+function buildSummaryText(results: BenchResult[]): string {
+  const W = 90;
+  const nameWidth = Math.max(30, ...results.map((r) => r.name.length + 2));
+  const lines: string[] = [];
+
+  lines.push("=".repeat(W));
+  lines.push("  SUMMARY");
+  lines.push("=".repeat(W));
+
+  const header =
+    "  " +
+    "Benchmark".padEnd(nameWidth) +
+    "Mean".padStart(12) +
+    "Median".padStart(12) +
+    "P99".padStart(12) +
+    "P99.9".padStart(12) +
+    "StdDev".padStart(12);
+  lines.push(header);
+  lines.push("  " + "-".repeat(header.length - 2));
+
+  for (const r of results) {
+    lines.push(
+      "  " +
+        r.name.padEnd(nameWidth) +
+        fmtMs(r.mean).padStart(12) +
+        fmtMs(r.median).padStart(12) +
+        fmtMs(r.p99).padStart(12) +
+        fmtMs(r.p999).padStart(12) +
+        fmtMs(r.stddev).padStart(12),
+    );
+  }
+
+  lines.push("=".repeat(W));
+  return lines.join("\n");
+}
+
+function createUI(): {
+  setStatus: (text: string) => void;
+  addResult: (r: BenchResult) => void;
+  setDone: (results: BenchResult[]) => void;
+} {
+  const app = document.getElementById("app")!;
+  app.innerHTML = "";
+
+  const style = document.createElement("style");
+  style.textContent = `
+		* { margin: 0; padding: 0; box-sizing: border-box; }
+		body { background: #0d1117; color: #c9d1d9; font-family: 'SF Mono', 'Cascadia Code', 'Fira Code', monospace; font-size: 14px; padding: 24px; }
+		h1 { color: #58a6ff; font-size: 20px; margin-bottom: 4px; }
+		.subtitle { color: #8b949e; font-size: 13px; margin-bottom: 20px; }
+		#status { color: #f0883e; margin-bottom: 16px; font-size: 13px; }
+		table { border-collapse: collapse; width: 100%; max-width: 1100px; }
+		th { text-align: left; padding: 8px 12px; border-bottom: 2px solid #30363d; color: #8b949e; font-weight: 600; font-size: 12px; text-transform: uppercase; letter-spacing: 0.5px; }
+		th.num { text-align: right; }
+		td { padding: 8px 12px; border-bottom: 1px solid #21262d; }
+		td.num { text-align: right; font-variant-numeric: tabular-nums; }
+		td.name { color: #58a6ff; font-weight: 500; }
+		tr:hover td { background: #161b22; }
+		.actions { margin-top: 16px; display: flex; gap: 8px; }
+		.actions button { padding: 8px 20px; border: none; border-radius: 6px; font-family: inherit; font-size: 14px; cursor: pointer; }
+		#run-btn { background: #238636; color: #fff; }
+		#run-btn:hover { background: #2ea043; }
+		#run-btn:disabled { background: #21262d; color: #484f58; cursor: not-allowed; }
+		#copy-btn { background: #30363d; color: #c9d1d9; display: none; }
+		#copy-btn:hover { background: #484f58; }
+		#summary-block { margin-top: 16px; display: none; }
+		#summary-block pre { background: #161b22; border: 1px solid #30363d; border-radius: 6px; padding: 16px; overflow-x: auto; white-space: pre; font-size: 13px; color: #e6edf3; }
+	`;
+  document.head.appendChild(style);
+
+  const h1 = document.createElement("h1");
+  h1.textContent = "Koota ECS Stress Test";
+  app.appendChild(h1);
+
+  const sub = document.createElement("div");
+  sub.className = "subtitle";
+  sub.textContent = `${ITERATIONS} iterations per benchmark`;
+  app.appendChild(sub);
+
+  const status = document.createElement("div");
+  status.id = "status";
+  app.appendChild(status);
+
+  const table = document.createElement("table");
+  const thead = document.createElement("thead");
+  const headerRow = document.createElement("tr");
+  const cols = [
+    "Benchmark",
+    "Mean",
+    "Median",
+    "Min",
+    "Max",
+    "P99",
+    "P99.9",
+    "StdDev",
+    "ops/s",
+  ];
+  for (const col of cols) {
+    const th = document.createElement("th");
+    th.textContent = col;
+    if (col !== "Benchmark") th.className = "num";
+    headerRow.appendChild(th);
+  }
+  thead.appendChild(headerRow);
+  table.appendChild(thead);
+
+  const tbody = document.createElement("tbody");
+  table.appendChild(tbody);
+  app.appendChild(table);
+
+  const actions = document.createElement("div");
+  actions.className = "actions";
+
+  const btn = document.createElement("button");
+  btn.id = "run-btn";
+  btn.textContent = "Run Again";
+  btn.disabled = true;
+  btn.onclick = () => {
+    tbody.innerHTML = "";
+    summaryBlock.style.display = "none";
+    copyBtn.style.display = "none";
+    runAll();
+  };
+  actions.appendChild(btn);
+
+  const copyBtn = document.createElement("button");
+  copyBtn.id = "copy-btn";
+  copyBtn.textContent = "Copy Summary";
+  actions.appendChild(copyBtn);
+
+  app.appendChild(actions);
+
+  const summaryBlock = document.createElement("div");
+  summaryBlock.id = "summary-block";
+  const summaryPre = document.createElement("pre");
+  summaryBlock.appendChild(summaryPre);
+  app.appendChild(summaryBlock);
+
+  return {
+    setStatus(text: string) {
+      status.textContent = text;
+    },
+    addResult(r: BenchResult) {
+      const tr = document.createElement("tr");
+      const vals = [
+        { text: r.name, cls: "name" },
+        { text: fmtMs(r.mean), cls: "num" },
+        { text: fmtMs(r.median), cls: "num" },
+        { text: fmtMs(r.min), cls: "num" },
+        { text: fmtMs(r.max), cls: "num" },
+        { text: fmtMs(r.p99), cls: "num" },
+        { text: fmtMs(r.p999), cls: "num" },
+        { text: fmtMs(r.stddev), cls: "num" },
+        { text: (1000 / r.mean).toFixed(1), cls: "num" },
+      ];
+      for (const v of vals) {
+        const td = document.createElement("td");
+        td.textContent = v.text;
+        td.className = v.cls;
+        tr.appendChild(td);
+      }
+      tbody.appendChild(tr);
+    },
+    setDone(results: BenchResult[]) {
+      status.textContent = "Done.";
+      btn.disabled = false;
+
+      const text = buildSummaryText(results);
+      summaryPre.textContent = text;
+      summaryBlock.style.display = "block";
+      copyBtn.style.display = "inline-block";
+      copyBtn.textContent = "Copy Summary";
+      copyBtn.onclick = () => {
+        navigator.clipboard.writeText(text).then(() => {
+          copyBtn.textContent = "Copied!";
+          setTimeout(() => {
+            copyBtn.textContent = "Copy Summary";
+          }, 1500);
+        });
+      };
+    },
+  };
+}
+
+const ui = createUI();
+
+function runAll() {
+  const btn = document.getElementById("run-btn") as HTMLButtonElement;
+  btn.disabled = true;
+
+  let idx = 0;
+  const results: BenchResult[] = [];
+
+  function next() {
+    if (idx >= suites.length) {
+      ui.setDone(results);
+      return;
+    }
+
+    const suite = suites[idx];
+    ui.setStatus(`Running ${idx + 1}/${suites.length}: ${suite.name}...`);
+
+    setTimeout(() => {
+      const result = suite.run();
+      ui.addResult(result);
+      results.push(result);
+      idx++;
+      next();
+    }, 50);
+  }
+
+  next();
+}
+
+runAll();
diff --git a/examples/apps/stress-test/tsconfig.json b/examples/apps/stress-test/tsconfig.json
@@ -0,0 +1,4 @@
+{
+	"extends": "@config/typescript/base.json",
+	"include": ["src"]
+}
diff --git a/examples/sims/n-body/src/constants.ts b/examples/sims/n-body/src/constants.ts
@@ -1,4 +1,4 @@
-const NBODIES = 2000; // Number of entities
+const NBODIES = 10000; // Number of entities
 const BASE_MASS = 0.1; // Base mass
 const VAR_MASS = 0.8; // Amount of randomness added to mass
 const INITIAL_C = 12000; // Mass used in calculation of orbital speed

diff --git a/examples/sims/stress-test/package.json b/examples/sims/stress-test/package.json
@@ -0,0 +1,14 @@
+{
+	"name": "@sim/stress-test",
+	"private": true,
+	"version": "0.0.1",
+	"description": "Comprehensive ECS stress test targeting BitSet, TraitData[], Query[], and micro-optimizations",
+	"type": "module",
+	"main": "./src/index.ts",
+	"dependencies": {
+		"koota": "workspace:*"
+	},
+	"devDependencies": {
+		"@config/typescript": "workspace:*"
+	}
+}