This content originally appeared on DEV Community and was authored by liu yang

Practical Guide to Performance Optimization of HarmonyOS Next

I. The Core Value of Performance Optimization

• User Experience: For every 10ms improvement in smoothness, user retention increases by 1.2% (Huawei Lab data).
• Resource Efficiency: A 30% reduction in memory usage can boost background survival rates by 50%.
• Ecosystem Requirements: The Huawei App Market strictly restricts the listing of applications with launch times exceeding 2 seconds.

II. Five Common Performance Issues and Solutions

1. UI Rendering Lag (FPS < 50)

• Problem Symptoms:
  

  // Common log snippet during lag
  [JS Frame] RenderTask cost 23ms (Threshold:16ms)
  

• Solutions:

  • Layout Optimization:

    // Incorrect example: Excessive container nesting
    Column() {
      Row() {
        Column() { /* ... */ }
      }
    }
  
    // Optimized solution: Use @Reusable for caching
    @Reusable
    struct OptimizedItem {
      build() { /* ... */ }
    }
  

  • Rendering Pipeline Control:

    // Enable asynchronous rendering
    Canvas.createRenderingContext('2d', { 
      asyncRender: true 
    })
  

2. Memory Leaks (OOM Rate > 0.1%)

• Typical Scenario Fixes:
  

  // Incorrect: Failing to unbind global events
  appEvent.on('systemEvent', this.callback)
  
  // Correct: Use lifecycle - aware subscriptions
  import { LifecycleEventObserver } from '@ohos.app.ability.UIAbility'
  const observer: LifecycleEventObserver = {
    onDestroy() {
      appEvent.off('systemEvent', this.callback)
    }
  }
  context.lifecycleManager.subscribe(observer)
  

3. Cold Start Duration (> 1.5s)

• Optimization Phase Breakdown:

4. Distributed Communication Latency

• Cross – Device Call Optimization:
  

  // Inefficient sequential calls
  deviceA.callMethod('getData')
    .then(() => deviceA.callMethod('process'))
    .then(() => deviceA.callMethod('sendResult'))
  
  // Optimized: Batch operation encapsulation
  @Concurrent
  async function batchOperation() {
    const proxy = await deviceA.getProxy()
    return await proxy.executePipeline()
  }
  

5. High Background Power Consumption

• Power Management Strategy:
  

  <!-- res/configuration.xml -->
  <abilities>
    <ability 
      backgroundModes="dataTransfer" 
      suspendTimeLimit="300" /> <!-- Limit background survival time -->
  </abilities>
  

III. Performance Optimization Best Practices

1. Deep Rendering Pipeline Optimization

• GPU Instruction Batching:
  

  // Enable DrawCall merging
  renderer.setRenderOption({
    batchThreshold: 50  // Maximum draw units per batch
  })
  

• Shader Pre – Compilation:
  

  // Generate SPIR - V bytecode during build
  hdc build --shader - optimize
  

2. New Paradigm for Memory Management

```typescript
// Use the new lightweight object pool
import { LightWeightPool } from '@ohos.performance'
const pool = new LightWeightPool(() => new BigDataObject(), 10)

// Acquire objects from the pool
const obj = pool.acquire()
```

3. Efficient Threading Model

This content originally appeared on DEV Community and was authored by liu yang