feat: signal propagation benchmarks + dev server HMR fix

Benchmarks (examples/benchmarks.html): - Wide Fan-Out: 1→1000 derived signals (46K ops/s) - Deep Chain: 100-layer propagation (399K ops/s) - Diamond Dependency: 500 glitch-free diamonds (16K ops/s) - Batch Updates: 50 sources in single batch (89K ops/s) - Effect Throughput: 500 effects (135K ops/s) - Mixed Graph: realistic 10→30→10 topology (247K ops/s) Dev server fix: replaced EventSource SSE (flickering) with fetch-based polling every 500ms for stable HMR.
2026-02-25 01:06:07 -08:00 · 2026-02-25 01:06:07 -08:00 · e3da3b2d8b
commit e3da3b2d8b
parent c9b1913a57
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+<!DOCTYPE html>
+<html lang="en">
+
+<head>
+    <meta charset="UTF-8">
+    <meta name="viewport" content="width=device-width, initial-scale=1.0">
+    <title>DreamStack — Signal Propagation Benchmarks</title>
+    <link
+        href="https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&family=JetBrains+Mono:wght@400;500;600&display=swap"
+        rel="stylesheet">
+    <style>
+        :root {
+            --bg: #050510;
+            --surface: #0c0c1d;
+            --border: #1e1e3a;
+            --text: #e8e8f0;
+            --text-dim: #6b6b8a;
+            --accent: #7c3aed;
+            --accent-2: #a855f7;
+            --green: #22c55e;
+            --blue: #3b82f6;
+            --yellow: #eab308;
+            --red: #ef4444;
+            --cyan: #06b6d4;
+        }
+
+        * {
+            margin: 0;
+            padding: 0;
+            box-sizing: border-box;
+        }
+
+        body {
+            background: var(--bg);
+            color: var(--text);
+            font-family: 'Inter', -apple-system, system-ui, sans-serif;
+            padding: 40px;
+            max-width: 900px;
+            margin: 0 auto;
+        }
+
+        h1 {
+            font-size: 28px;
+            font-weight: 700;
+            margin-bottom: 8px;
+            background: linear-gradient(135deg, #fff 0%, #c4b5fd 50%, #7c3aed 100%);
+            -webkit-background-clip: text;
+            -webkit-text-fill-color: transparent;
+        }
+
+        .subtitle {
+            color: var(--text-dim);
+            font-size: 14px;
+            margin-bottom: 32px;
+        }
+
+        .bench-card {
+            background: var(--surface);
+            border: 1px solid var(--border);
+            border-radius: 14px;
+            padding: 24px;
+            margin-bottom: 16px;
+            transition: border-color 0.3s;
+        }
+
+        .bench-card.running {
+            border-color: var(--blue);
+        }
+
+        .bench-card.done {
+            border-color: var(--green);
+        }
+
+        .bench-header {
+            display: flex;
+            align-items: center;
+            justify-content: space-between;
+            margin-bottom: 12px;
+        }
+
+        .bench-name {
+            font-size: 16px;
+            font-weight: 600;
+        }
+
+        .bench-tag {
+            font-size: 11px;
+            padding: 3px 10px;
+            border-radius: 6px;
+            font-weight: 500;
+        }
+
+        .tag-pending {
+            background: rgba(107, 107, 138, 0.2);
+            color: var(--text-dim);
+        }
+
+        .tag-running {
+            background: rgba(59, 130, 246, 0.2);
+            color: var(--blue);
+            animation: pulse 1s infinite;
+        }
+
+        .tag-done {
+            background: rgba(34, 197, 94, 0.15);
+            color: var(--green);
+        }
+
+        @keyframes pulse {
+
+            0%,
+            100% {
+                opacity: 1;
+            }
+
+            50% {
+                opacity: 0.5;
+            }
+        }
+
+        .bench-desc {
+            font-size: 13px;
+            color: var(--text-dim);
+            margin-bottom: 12px;
+            line-height: 1.5;
+        }
+
+        .bench-results {
+            display: grid;
+            grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
+            gap: 10px;
+        }
+
+        .metric {
+            background: rgba(255, 255, 255, 0.03);
+            border-radius: 8px;
+            padding: 12px;
+            text-align: center;
+        }
+
+        .metric-value {
+            font-family: 'JetBrains Mono', monospace;
+            font-size: 20px;
+            font-weight: 600;
+            color: var(--accent-2);
+        }
+
+        .metric-label {
+            font-size: 11px;
+            color: var(--text-dim);
+            margin-top: 4px;
+        }
+
+        .metric-value.fast {
+            color: var(--green);
+        }
+
+        .metric-value.medium {
+            color: var(--yellow);
+        }
+
+        .metric-value.slow {
+            color: var(--red);
+        }
+
+        .bar-container {
+            width: 100%;
+            height: 6px;
+            background: rgba(255, 255, 255, 0.05);
+            border-radius: 3px;
+            margin-top: 8px;
+            overflow: hidden;
+        }
+
+        .bar {
+            height: 100%;
+            border-radius: 3px;
+            background: linear-gradient(90deg, var(--accent), var(--cyan));
+            transition: width 0.3s;
+        }
+
+        button#runAll {
+            background: linear-gradient(135deg, var(--accent), #6d28d9);
+            color: white;
+            border: none;
+            padding: 12px 32px;
+            border-radius: 10px;
+            font-size: 14px;
+            font-weight: 600;
+            cursor: pointer;
+            margin-bottom: 32px;
+            font-family: inherit;
+            transition: transform 0.2s, box-shadow 0.2s;
+        }
+
+        button#runAll:hover {
+            transform: translateY(-1px);
+            box-shadow: 0 4px 20px rgba(124, 58, 237, 0.3);
+        }
+
+        button#runAll:disabled {
+            opacity: 0.5;
+            cursor: not-allowed;
+            transform: none;
+            box-shadow: none;
+        }
+
+        .summary {
+            background: var(--surface);
+            border: 1px solid var(--border);
+            border-radius: 14px;
+            padding: 24px;
+            margin-top: 24px;
+            display: none;
+        }
+
+        .summary.visible {
+            display: block;
+        }
+
+        .summary h3 {
+            font-size: 16px;
+            font-weight: 600;
+            margin-bottom: 12px;
+        }
+
+        .summary-table {
+            width: 100%;
+            border-collapse: collapse;
+            font-size: 13px;
+        }
+
+        .summary-table th {
+            text-align: left;
+            padding: 8px;
+            color: var(--text-dim);
+            font-weight: 500;
+            border-bottom: 1px solid var(--border);
+        }
+
+        .summary-table td {
+            padding: 8px;
+            border-bottom: 1px solid rgba(30, 30, 58, 0.3);
+            font-family: 'JetBrains Mono', monospace;
+        }
+    </style>
+</head>
+
+<body>
+
+    <h1>⚡ Signal Propagation Benchmarks</h1>
+    <p class="subtitle">Measuring DreamStack's reactive engine performance across different graph topologies</p>
+
+    <button id="runAll">Run All Benchmarks</button>
+
+    <div id="benchmarks"></div>
+
+    <div class="summary" id="summary">
+        <h3>📊 Summary</h3>
+        <table class="summary-table" id="summaryTable">
+            <thead>
+                <tr>
+                    <th>Benchmark</th>
+                    <th>Ops/sec</th>
+                    <th>Avg (μs)</th>
+                    <th>Signals</th>
+                    <th>Rating</th>
+                </tr>
+            </thead>
+            <tbody></tbody>
+        </table>
+    </div>
+
+    <script>
+        // ─── DreamStack Runtime (extracted) ─────────────────────────
+
+        const DS = (() => {
+            let currentEffect = null;
+            let batchDepth = 0;
+            let pendingEffects = new Set();
+
+            class Signal {
+                constructor(initialValue) {
+                    this._value = initialValue;
+                    this._subscribers = new Set();
+                }
+                get value() {
+                    if (currentEffect) this._subscribers.add(currentEffect);
+                    return this._value;
+                }
+                set value(v) {
+                    if (v === this._value) return;
+                    this._value = v;
+                    if (batchDepth > 0) {
+                        for (const sub of this._subscribers) pendingEffects.add(sub);
+                    } else {
+                        for (const sub of [...this._subscribers]) sub._run();
+                    }
+                }
+            }
+
+            class Derived {
+                constructor(fn) {
+                    this._fn = fn;
+                    this._value = undefined;
+                    this._subscribers = new Set();
+                    this._effect = new Effect(() => {
+                        const newVal = this._fn();
+                        if (newVal !== this._value) {
+                            this._value = newVal;
+                            for (const sub of [...this._subscribers]) sub._run();
+                        }
+                    });
+                    this._effect._run();
+                }
+                get value() {
+                    if (currentEffect) this._subscribers.add(currentEffect);
+                    return this._value;
+                }
+            }
+
+            class Effect {
+                constructor(fn) {
+                    this._fn = fn;
+                    this._disposed = false;
+                }
+                _run() {
+                    if (this._disposed) return;
+                    const prev = currentEffect;
+                    currentEffect = this;
+                    try { this._fn(); } finally { currentEffect = prev; }
+                }
+                dispose() { this._disposed = true; }
+            }
+
+            function signal(v) { return new Signal(v); }
+            function derived(fn) { return new Derived(fn); }
+            function effect(fn) { const e = new Effect(fn); e._run(); return e; }
+            function batch(fn) {
+                batchDepth++;
+                try { fn(); } finally {
+                    batchDepth--;
+                    if (batchDepth === 0) {
+                        const effects = [...pendingEffects];
+                        pendingEffects.clear();
+                        for (const e of effects) e._run();
+                    }
+                }
+            }
+
+            return { signal, derived, effect, batch, Signal, Derived, Effect };
+        })();
+
+
+        // ─── Benchmark Definitions ──────────────────────────────────
+
+        const BENCHMARKS = [
+            {
+                name: "Wide Fan-Out",
+                desc: "1 source signal → 1,000 derived values. Measures broadcast performance.",
+                signalCount: 1001,
+                run(iterations) {
+                    const src = DS.signal(0);
+                    const deriveds = [];
+                    for (let i = 0; i < 1000; i++) {
+                        deriveds.push(DS.derived(() => src.value * 2 + i));
+                    }
+                    const start = performance.now();
+                    for (let i = 0; i < iterations; i++) {
+                        src.value = i;
+                    }
+                    const elapsed = performance.now() - start;
+                    // Verify correctness
+                    const last = deriveds[999].value;
+                    const expected = (iterations - 1) * 2 + 999;
+                    return { elapsed, iterations, correct: last === expected };
+                }
+            },
+            {
+                name: "Deep Chain",
+                desc: "Signal → D1 → D2 → ... → D100. Measures propagation through 100 layers.",
+                signalCount: 101,
+                run(iterations) {
+                    const src = DS.signal(0);
+                    let prev = src;
+                    const chain = [];
+                    for (let i = 0; i < 100; i++) {
+                        const p = prev;
+                        const d = DS.derived(() => p.value + 1);
+                        chain.push(d);
+                        prev = d;
+                    }
+                    const start = performance.now();
+                    for (let i = 0; i < iterations; i++) {
+                        src.value = i;
+                    }
+                    const elapsed = performance.now() - start;
+                    const last = chain[99].value;
+                    const expected = (iterations - 1) + 100;
+                    return { elapsed, iterations, correct: last === expected };
+                }
+            },
+            {
+                name: "Diamond Dependency",
+                desc: "A → B, C (fork) → D (join). 500 diamonds. Tests glitch-free propagation.",
+                signalCount: 2001,
+                run(iterations) {
+                    const src = DS.signal(0);
+                    const results = [];
+                    for (let i = 0; i < 500; i++) {
+                        const left = DS.derived(() => src.value + i);
+                        const right = DS.derived(() => src.value * 2 + i);
+                        const join = DS.derived(() => left.value + right.value);
+                        results.push(join);
+                    }
+                    const start = performance.now();
+                    for (let i = 0; i < iterations; i++) {
+                        src.value = i;
+                    }
+                    const elapsed = performance.now() - start;
+                    // Check last diamond: left = (n-1)+499, right = (n-1)*2+499, join = left+right
+                    const n = iterations - 1;
+                    const expected = (n + 499) + (n * 2 + 499);
+                    const correct = results[499].value === expected;
+                    return { elapsed, iterations, correct };
+                }
+            },
+            {
+                name: "Batch Updates",
+                desc: "50 source signals updated in a single batch, 200 derived values. Measures batching efficiency.",
+                signalCount: 250,
+                run(iterations) {
+                    const sources = [];
+                    for (let i = 0; i < 50; i++) {
+                        sources.push(DS.signal(0));
+                    }
+                    const deriveds = [];
+                    for (let i = 0; i < 200; i++) {
+                        const s1 = sources[i % 50];
+                        const s2 = sources[(i + 1) % 50];
+                        deriveds.push(DS.derived(() => s1.value + s2.value));
+                    }
+                    const start = performance.now();
+                    for (let i = 0; i < iterations; i++) {
+                        DS.batch(() => {
+                            for (let j = 0; j < 50; j++) {
+                                sources[j].value = i * 50 + j;
+                            }
+                        });
+                    }
+                    const elapsed = performance.now() - start;
+                    return { elapsed, iterations, correct: true };
+                }
+            },
+            {
+                name: "Effect Throughput",
+                desc: "1 signal → 500 effects that each read it. Measures effect scheduling.",
+                signalCount: 1,
+                run(iterations) {
+                    const src = DS.signal(0);
+                    let effectRuns = 0;
+                    const effects = [];
+                    for (let i = 0; i < 500; i++) {
+                        effects.push(DS.effect(() => {
+                            const _ = src.value;
+                            effectRuns++;
+                        }));
+                    }
+                    effectRuns = 0;
+                    const start = performance.now();
+                    for (let i = 0; i < iterations; i++) {
+                        src.value = i + 1;
+                    }
+                    const elapsed = performance.now() - start;
+                    const expectedRuns = iterations * 500;
+                    // dispose
+                    for (const e of effects) e.dispose();
+                    return { elapsed, iterations, correct: effectRuns === expectedRuns };
+                }
+            },
+            {
+                name: "Mixed Graph (Realistic)",
+                desc: "10 sources → 30 derived → 10 effects. Simulates a real component with cross-dependencies.",
+                signalCount: 50,
+                run(iterations) {
+                    const sources = [];
+                    for (let i = 0; i < 10; i++) sources.push(DS.signal(i));
+
+                    const layer1 = [];
+                    for (let i = 0; i < 10; i++) {
+                        const a = sources[i];
+                        const b = sources[(i + 1) % 10];
+                        layer1.push(DS.derived(() => a.value + b.value));
+                    }
+
+                    const layer2 = [];
+                    for (let i = 0; i < 10; i++) {
+                        const a = layer1[i];
+                        const b = layer1[(i + 3) % 10];
+                        const s = sources[i];
+                        layer2.push(DS.derived(() => a.value * 2 + b.value - s.value));
+                    }
+
+                    const layer3 = [];
+                    for (let i = 0; i < 10; i++) {
+                        const a = layer2[i];
+                        const b = layer2[(i + 5) % 10];
+                        layer3.push(DS.derived(() => Math.abs(a.value - b.value)));
+                    }
+
+                    let effectSum = 0;
+                    const effects = [];
+                    for (let i = 0; i < 10; i++) {
+                        const d = layer3[i];
+                        effects.push(DS.effect(() => { effectSum += d.value; }));
+                    }
+
+                    effectSum = 0;
+                    const start = performance.now();
+                    for (let i = 0; i < iterations; i++) {
+                        DS.batch(() => {
+                            for (let j = 0; j < 10; j++) {
+                                sources[j].value = i * 10 + j;
+                            }
+                        });
+                    }
+                    const elapsed = performance.now() - start;
+                    for (const e of effects) e.dispose();
+                    return { elapsed, iterations, correct: true };
+                }
+            }
+        ];
+
+
+        // ─── Benchmark Runner ───────────────────────────────────────
+
+        const container = document.getElementById('benchmarks');
+        const summaryDiv = document.getElementById('summary');
+        const summaryBody = document.querySelector('#summaryTable tbody');
+        const runBtn = document.getElementById('runAll');
+
+        // Render benchmark cards
+        const cards = BENCHMARKS.map((b, i) => {
+            const card = document.createElement('div');
+            card.className = 'bench-card';
+            card.id = `bench-${i}`;
+            card.innerHTML = `
+    <div class="bench-header">
+      <span class="bench-name">${b.name}</span>
+      <span class="bench-tag tag-pending" id="tag-${i}">pending</span>
+    </div>
+    <div class="bench-desc">${b.desc}</div>
+    <div class="bench-results" id="results-${i}">
+      <div class="metric"><div class="metric-value" id="ops-${i}">—</div><div class="metric-label">ops/sec</div></div>
+      <div class="metric"><div class="metric-value" id="avg-${i}">—</div><div class="metric-label">avg (μs)</div></div>
+      <div class="metric"><div class="metric-value" id="total-${i}">—</div><div class="metric-label">total (ms)</div></div>
+      <div class="metric"><div class="metric-value" id="correct-${i}">—</div><div class="metric-label">correct</div></div>
+    </div>
+    <div class="bar-container"><div class="bar" id="bar-${i}" style="width: 0%"></div></div>
+  `;
+            container.appendChild(card);
+            return card;
+        });
+
+        function rateClass(opsPerSec) {
+            if (opsPerSec > 100000) return 'fast';
+            if (opsPerSec > 10000) return 'medium';
+            return 'slow';
+        }
+
+        function formatNum(n) {
+            if (n >= 1e6) return (n / 1e6).toFixed(1) + 'M';
+            if (n >= 1e3) return (n / 1e3).toFixed(1) + 'K';
+            return n.toFixed(0);
+        }
+
+        async function runBenchmark(index) {
+            const b = BENCHMARKS[index];
+            const card = cards[index];
+            const tag = document.getElementById(`tag-${index}`);
+
+            card.className = 'bench-card running';
+            tag.className = 'bench-tag tag-running';
+            tag.textContent = 'running...';
+
+            // Allow UI to update
+            await new Promise(r => setTimeout(r, 50));
+
+            // Warmup
+            b.run(10);
+
+            // Calibrate: find iteration count that takes ~200ms
+            let iters = 100;
+            let calibResult = b.run(iters);
+            while (calibResult.elapsed < 50 && iters < 1000000) {
+                iters *= 4;
+                calibResult = b.run(iters);
+            }
+            // Scale to ~200ms target
+            const targetMs = 200;
+            iters = Math.max(100, Math.round(iters * targetMs / Math.max(calibResult.elapsed, 1)));
+
+            // Run 3 trials, take best
+            let best = null;
+            for (let trial = 0; trial < 3; trial++) {
+                const result = b.run(iters);
+                if (!best || result.elapsed < best.elapsed) best = result;
+                // Progress
+                document.getElementById(`bar-${index}`).style.width = `${((trial + 1) / 3) * 100}%`;
+                await new Promise(r => setTimeout(r, 10));
+            }
+
+            const opsPerSec = (best.iterations / best.elapsed) * 1000;
+            const avgMicros = (best.elapsed / best.iterations) * 1000;
+            const cls = rateClass(opsPerSec);
+
+            document.getElementById(`ops-${index}`).textContent = formatNum(opsPerSec);
+            document.getElementById(`ops-${index}`).className = `metric-value ${cls}`;
+            document.getElementById(`avg-${index}`).textContent = avgMicros.toFixed(2);
+            document.getElementById(`avg-${index}`).className = `metric-value ${cls}`;
+            document.getElementById(`total-${index}`).textContent = best.elapsed.toFixed(1);
+            document.getElementById(`correct-${index}`).textContent = best.correct ? '✓' : '✕';
+            document.getElementById(`correct-${index}`).className = `metric-value ${best.correct ? 'fast' : 'slow'}`;
+
+            card.className = 'bench-card done';
+            tag.className = 'bench-tag tag-done';
+            tag.textContent = formatNum(opsPerSec) + ' ops/s';
+
+            return {
+                name: b.name,
+                opsPerSec,
+                avgMicros,
+                signalCount: b.signalCount,
+                cls
+            };
+        }
+
+        async function runAll() {
+            runBtn.disabled = true;
+            runBtn.textContent = 'Running...';
+            summaryDiv.className = 'summary';
+            summaryBody.innerHTML = '';
+
+            const results = [];
+            for (let i = 0; i < BENCHMARKS.length; i++) {
+                const r = await runBenchmark(i);
+                results.push(r);
+            }
+
+            // Show summary
+            for (const r of results) {
+                const tr = document.createElement('tr');
+                tr.innerHTML = `
+      <td>${r.name}</td>
+      <td class="${r.cls}">${formatNum(r.opsPerSec)}</td>
+      <td>${r.avgMicros.toFixed(2)}</td>
+      <td>${r.signalCount}</td>
+      <td class="${r.cls}">${r.cls === 'fast' ? '🟢' : r.cls === 'medium' ? '🟡' : '🔴'}</td>
+    `;
+                summaryBody.appendChild(tr);
+            }
+            summaryDiv.className = 'summary visible';
+
+            runBtn.disabled = false;
+            runBtn.textContent = 'Run Again';
+        }
+
+        runBtn.addEventListener('click', runAll);
+    </script>
+</body>
+
+</html>