map.go

     1  // Copyright 2016 The Go Authors. All rights reserved.
     2  // Use of this source code is governed by a BSD-style
     3  // license that can be found in the LICENSE file.
     4  
     5  package main
     6  
     7  import "runtime"
     8  
     9  func init() {
    10  	register("concurrentMapWrites", concurrentMapWrites)
    11  	register("concurrentMapReadWrite", concurrentMapReadWrite)
    12  	register("concurrentMapIterateWrite", concurrentMapIterateWrite)
    13  }
    14  
    15  func concurrentMapWrites() {
    16  	m := map[int]int{}
    17  	c := make(chan struct{})
    18  	go func() {
    19  		for i := 0; i < 10000; i++ {
    20  			m[5] = 0
    21  			runtime.Gosched()
    22  		}
    23  		c <- struct{}{}
    24  	}()
    25  	go func() {
    26  		for i := 0; i < 10000; i++ {
    27  			m[6] = 0
    28  			runtime.Gosched()
    29  		}
    30  		c <- struct{}{}
    31  	}()
    32  	<-c
    33  	<-c
    34  }
    35  
    36  func concurrentMapReadWrite() {
    37  	m := map[int]int{}
    38  	c := make(chan struct{})
    39  	go func() {
    40  		for i := 0; i < 10000; i++ {
    41  			m[5] = 0
    42  			runtime.Gosched()
    43  		}
    44  		c <- struct{}{}
    45  	}()
    46  	go func() {
    47  		for i := 0; i < 10000; i++ {
    48  			_ = m[6]
    49  			runtime.Gosched()
    50  		}
    51  		c <- struct{}{}
    52  	}()
    53  	<-c
    54  	<-c
    55  }
    56  
    57  func concurrentMapIterateWrite() {
    58  	m := map[int]int{}
    59  	c := make(chan struct{})
    60  	go func() {
    61  		for i := 0; i < 10000; i++ {
    62  			m[5] = 0
    63  			runtime.Gosched()
    64  		}
    65  		c <- struct{}{}
    66  	}()
    67  	go func() {
    68  		for i := 0; i < 10000; i++ {
    69  			for range m {
    70  			}
    71  			runtime.Gosched()
    72  		}
    73  		c <- struct{}{}
    74  	}()
    75  	<-c
    76  	<-c
    77  }
    78
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