docs: channel 生产者/消费者

base/channel/example/main.go

@@ -2,6 +2,7 @@ package main
 
 import (
 	"fmt"
+	"runtime"
 	"sync"
 	"sync/atomic"
 )
@@ -12,7 +13,7 @@ var consumer = int32(0)
 
 func f1(ch chan int) {
 	defer wg.Done()
-	for i := 0; i < 100; i++ {
+	for i := 0; i < 1_000_000; i++ {
 		ch <- i
 	}
 
@@ -23,7 +24,7 @@ func f1(ch chan int) {
 func f2(in chan int, out chan int) {
 	defer wg.Done()
 	for i := range in {
-		out <- i * i
+		out <- i
 	}
 
 	if atomic.AddInt32(&consumer, -1) <= 0 {
@@ -33,16 +34,18 @@ func f2(in chan int, out chan int) {
 }
 
 func main() {
-	ch := make(chan int, 20)
+	ch := make(chan int, 50)
 	ch2 := make(chan int, 5)
 
 	wg.Add(1)
 	go f1(ch)
 
-	wg.Add(2)
+	wg.Add(runtime.NumCPU())
-	atomic.AddInt32(&consumer, 2)
+	atomic.AddInt32(&consumer, int32(runtime.NumCPU()))
-	go f2(ch, ch2)
+
+	for i := 0; i < runtime.NumCPU(); i++ {
 		go f2(ch, ch2)
+	}
 
 	for i := range ch2 {
 		fmt.Println(i)