52 lines
1.1 KiB
Go
52 lines
1.1 KiB
Go
package main
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import (
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"fmt"
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"runtime"
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"sync"
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"time"
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)
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var globalSum int64
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// 进一步增加循环次数，单任务耗时延长到10秒以上
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func longCPUTask(id int) {
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localSum := int64(0)
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loopCount := int64(500000000) * int64(id+1) // 循环次数：5e8→2e9（耗时≈10s→40s）
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for j := int64(1); j < loopCount; j++ {
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localSum = (localSum + j*j%987654321) * 1000000007 % 123456789
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if j%100000000 == 0 { // 极低频率写入全局变量，最大化独占P时间
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globalSum = localSum
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}
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}
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}
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func main() {
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runtime.GOMAXPROCS(1)
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var wg sync.WaitGroup
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startTime := time.Now()
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taskDurations := make([]time.Duration, 4)
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for i := 0; i < 4; i++ {
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wg.Add(1)
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id := i
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go func() {
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defer wg.Done()
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taskStart := time.Now()
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longCPUTask(id)
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taskDurations[id] = time.Since(taskStart)
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}()
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}
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wg.Wait()
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totalDuration := time.Since(startTime)
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fmt.Println("GOMAXPROCS=1")
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sumDurations := time.Duration(0)
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for i := 0; i < 4; i++ {
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fmt.Printf("任务%d 耗时: %v\n", i, taskDurations[i])
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sumDurations += taskDurations[i]
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}
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fmt.Printf("总耗时: %v, 4个任务之和: %v（接近）\n", totalDuration, sumDurations)
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}
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