我的服务器运行了一段时间,创建了大约200个连接并进行了一些计算并关闭,我发现它占用了大约2,7G的内存并且在几天之后从未减少过。程序本身并没有占用那么多,我通过memstats
检查了它。通过cat /proc/11686/status | grep -i threads
我得到Threads: 177
,所以我认为它占用了大量内存的原因是它创建了很多线程。为什么go
创建了这么多线程?是因为我使用了太多go func()
吗?我确信goroutines没有增加,他们正常退出。
PS
我的程序中有很多代码,所以我排除了细节,只需保留主要的
我的问题是go
创建一个线程来做某事。拥有这么多线程是正常的吗?我认为它对代码并不重视。
main.go
package main
import (
"sanguo/base/log"
"fmt"
"runtime"
"math/rand"
"time"
"net"
"os"
)
type GameServer struct {
Host string
}
func (server *GameServer) Start() {
// load system data
log.Debug("/*************************SREVER START********************************/")
tcpAddr, err := net.ResolveTCPAddr("tcp4", server.Host)
if err != nil {
log.Error(err.Error())
os.Exit(-1)
}
go func(){
for{
select {
case <-time.After(30*time.Second):
LookUp("read memstats")
}
}
}()
listener, err := net.ListenTCP("tcp", tcpAddr)
if err != nil {
log.Error(err.Error())
os.Exit(-1)
}
log.Debug("/*************************SERVER SUCC********************************/")
for {
conn, err := listener.AcceptTCP()
if err != nil {
continue
}
log.Debug("Accept a new connection ", conn.RemoteAddr())
go handleClient(conn)
}
}
func handleClient(conn *net.TCPConn) {
sess := NewSession(conn)
sess.Start()
}
func main() {
rand.Seed(time.Now().Unix())
runtime.GOMAXPROCS(runtime.NumCPU())
log.SetLevel(0)
filew := log.NewFileWriter("log", true)
err := filew.StartLogger()
if err != nil {
fmt.Println("Failed start log",err)
return
}
var server GameServer
server.Host = "127.0.0.1:9999"
server.Start()
}
session.go
package main
import (
"io"
"encoding/binary"
"encoding/json"
"github.com/felixge/tcpkeepalive"
"net"
"sanguo/base/log"
"strings"
"sync"
"time"
)
type Session struct {
conn *net.TCPConn //the tcp connection from client
recvChan chan *bufferedManager.Token //data from client
closeNotiChan chan bool //
ok bool
lock sync.Mutex
}
func NewSession(connection *net.TCPConn) (sess *Session) {
var client Session
client.conn = connection
client.recvChan = make(chan []byte, 1024)
client.closeNotiChan = make(chan bool)
client.ok = true
log.Debug("New Connection", &client)
kaConn, err := tcpkeepalive.EnableKeepAlive(connection)
if err != nil {
log.Debug("EnableKeepAlive err ", err)
} else {
kaConn.SetKeepAliveIdle(120 * time.Second)
kaConn.SetKeepAliveCount(4)
kaConn.SetKeepAliveInterval(5 * time.Second)
}
return &client
}
func (sess *Session) Close() {
sess.lock.Lock()
if sess.ok {
sess.ok = false
close(sess.closeNotiChan)
sess.conn.Close()
log.Trace("Sess Close Succ", sess, sess.uid)
}
sess.lock.Unlock()
}
func (sess *Session) handleRecv() {
defer func(){
if err := recover(); err != nil {
log.Critical("Panic", err)
}
log.Trace("Session Recv Exit", sess, sess.uid)
sess.Close()
}()
ch := sess.recvChan
header := make([]byte, 2)
for {
/**block until recieve len(header)**/
n, err := io.ReadFull(sess.conn, header)
if n == 0 && err == io.EOF {
//Opposite socket is closed
log.Warn("Socket Read EOF And Close", sess)
break
} else if err != nil {
//Sth wrong with this socket
log.Warn("Socket Wrong:", err)
break
}
size := binary.LittleEndian.Uint16(header) + 4
data := make([]byte, size)
n, err = io.ReadFull(sess.conn, t.Data)
if n == 0 && err == io.EOF {
log.Warn("Socket Read EOF And Close", sess)
break
} else if err != nil {
log.Warn("Socket Wrong:", err)
break
}
ch <- data //send data to Client to process
}
}
func (sess *Session) handleDispatch() {
defer func(){
log.Trace("Session Dispatch Exit", sess, sess.uid)
sess.Close()
}()
for {
select {
case msg, _ := <-sess.recvChan:
log.Debug("msg", msg)
sess.SendDirectly("helloworldhellowor", 1)
case <-sess.closeNotiChan:
return
}
}
}
func (sess *Session) Start() {
defer func() {
if err := recover(); err != nil {
log.Critical("Panic", err)
}
}()
go sess.handleRecv()
sess.handleDispatch()
close(sess.recvChan)
log.Warn("Session Start Exit", sess, sess.uid)
}
func (sess *Session) SendDirectly(back interface{}, op int) bool {
back_json, err := json.Marshal(back)
if err != nil {
log.Error("Can't encode json message ", err, back)
return false
}
log.Debug(sess.uid, "OUT cmd:", op, string(back_json))
_, err = sess.conn.Write(back_json)
if err != nil {
log.Error("send fail", err)
return false
}
return true
}
答案 0 :(得分:6)
使用Go,您可以创建许多goroutine,它不应该增加线程数。在您的代码中,运行Go代码的线程数受到runtime.NumCPU()。
的限制当goroutine必须执行阻塞调用(例如系统调用)或通过cgo调用C库时,可能会创建一个线程。在这种情况下,运行时调度程序从其调度池中删除运行goroutine的线程。如果调度池的线程数少于GOMAXPROCS,则将创建一个新的线程。
您可以在此处找到有关其工作原理的更多信息: https://softwareengineering.stackexchange.com/questions/222642/are-go-langs-goroutine-pools-just-green-threads/222694#222694
要理解代码生成线程的原因,您必须调查导致阻塞系统调用或C调用的所有代码路径。请注意,网络相关的调用是非阻塞的,因为它们由标准库自动复用。但是,如果执行某些磁盘I / O或调用外部库,则会生成线程。
例如,代码中使用的日志库可能会执行一些阻塞I / O,导致创建线程(特别是如果生成的文件托管在慢速设备上)。