TaskPool线程内存如何共享?

Question

TaskPool线程内存如何共享

Answer 1

TaskPool底层模型为Actor模型，本身线程间隔离，内存不共享。目前可以通过传输可共享对象SharedArrayBuffer达到内存共享的目的。

但需要注意，SharedArrayBuffer对象存储的数据在同时被修改时，需要通过原子操作保证其同步性，即下个操作开始之前务必需要等到上个操作已经结束。

参考代码如下：

import { taskpool } from '@kit.ArkTS'; 
 
@Concurrent 
function producer(ArrayBuffer: Int32Array): void { 
  let i32a = ArrayBuffer; 
  console.info("Producer: received sab"); 
  setInterval(() => { 
    let length = i32a.length; 
    for (let i = 1; i < length; i++) { 
      i32a[i] = Math.random() * length; 
    } 
    Atomics.notify(i32a, 0, 1); // notify customer 
  }, 2000); 
} 
 
@Concurrent 
function consumer(ArrayBuffer: Int32Array): void { 
  let i32a = ArrayBuffer; 
  console.info("Customer: received sab"); 
  while (true) { 
    Atomics.wait(i32a, 0, 0); 
    let length = i32a.length; 
    for (let i = length - 1; i > 0; i--) { 
      console.info("arraybuffer " + i + " value is " + i32a[i]); 
      i32a[i] = i; 
    } 
  } 
} 
 
function ArrayBufferShared(ArrayBuffer: Int32Array): void { 
  let group: taskpool.TaskGroup = new taskpool.TaskGroup(); 
  group.addTask(consumer, ArrayBuffer); 
  group.addTask(producer, ArrayBuffer); 
  taskpool.execute(group, taskpool.Priority.HIGH).then((ret: Object) => { 
    // 结果数组汇总处理 
  }) 
} 
 
@Entry 
@Component 
struct Index { 
  build() { 
    Row() { 
      Column() { 
        Text('Click') 
          .fontSize(50) 
          .fontWeight(FontWeight.Bold) 
          .onClick(() => { 
            let sab = new SharedArrayBuffer(32); 
            let i32a = new Int32Array(sab); 
            ArrayBufferShared(i32a); 
          }) 
      } 
      .width('100%') 
    } 
    .height('100%') 
  } 
}

参考链接

@ohos.taskpool（启动任务池）
多线程并发概述 (TaskPool和Worker)
Actor模型
可共享对象