github.com/nibnait/go-learn@v0.0.0-20220227013611-dfa47ea6d2da/src/test/chapter/ch4/25_share_mem_test.go (about)

     1  package ch4
     2  
     3  import (
     4  	"sync"
     5  	"testing"
     6  	"time"
     7  )
     8  
     9  func TestCounter(t *testing.T) {
    10  
    11  	counter := 0
    12  	for i := 0; i < 5000; i++ {
    13  		go func() {
    14  			counter++
    15  		}()
    16  	}
    17  	time.Sleep(1 * time.Second)
    18  	t.Logf("counter = %d", counter)
    19  
    20  }
    21  
    22  // lock unlock --> sync.Mutex
    23  func TestCounterThreadSafeMutex(t *testing.T) {
    24  	var mut sync.Mutex
    25  	counter := 0
    26  	for i := 0; i < 5000; i++ {
    27  		go func() {
    28  			defer func() {
    29  				mut.Unlock()
    30  			}()
    31  
    32  			mut.Lock()
    33  			counter++
    34  		}()
    35  	}
    36  	time.Sleep(1 * time.Second)
    37  	t.Logf("counter = %d", counter)
    38  }
    39  
    40  // lock unlock --> sync.RWLock ✅ 读多写少时，性能更好
    41  func TestCounterThreadSafeRWLock(t *testing.T) {
    42  	var rwMutex sync.RWMutex
    43  	counter := 0
    44  	for i := 0; i < 5000; i++ {
    45  		go func() {
    46  			defer func() {
    47  				rwMutex.Unlock()
    48  			}()
    49  
    50  			rwMutex.Lock()
    51  			counter++
    52  		}()
    53  	}
    54  	time.Sleep(1 * time.Second)
    55  	t.Logf("counter = %d", counter)
    56  }
    57  
    58  // thread.join -> sync.WaitGroup(.Add(1), .Done, .Wait)
    59  func TestCounterWaitGroup(t *testing.T) {
    60  	var mut sync.Mutex
    61  	var wg sync.WaitGroup
    62  	counter := 0
    63  	for i := 0; i < 5000; i++ {
    64  		wg.Add(1)
    65  		go func() {
    66  			defer func() {
    67  				mut.Unlock()
    68  			}()
    69  
    70  			mut.Lock()
    71  			counter++
    72  
    73  			wg.Done()
    74  		}()
    75  	}
    76  
    77  	wg.Wait()
    78  	t.Logf("counter = %d", counter)
    79  }