networking - Go package syscall conn.Read() is non-blocking and cause high CPU usage -

strangely, in case read() non-blocking , caused high cpu usage.

my code:

in function main:

l, err := net.listen("tcp", ":13798")   if err != nil {     log.fatal(err)   }    {     // wait connection.     conn, err := l.accept()     if err != nil {       log.fatal(err)     }     // handle connection in new goroutine.     // loop returns accepting,     // multiple connections may served concurrently.     go reqhandler.tcphandler(conn)      runtime.gosched()   } 

function tcphandler:

func tcphandler(conn net.conn) { request := make([]byte, 4096)   {     read_len, err := conn.read(request)      if err != nil {         if err.error() == "use of closed network connection" {         log("conn closed, error might happened")         break       }        neterr, ok := err.(net.error);       if ok && neterr.timeout() {         fmt.println(neterr)         log("client timeout!")         break       }     }      if read_len == 0 {      log("nothing read")       continue     } else {       //     }     request := make([]byte, 4096)   } } 

the problem is, conn.read() non-blocking, every time goes log("nothing read") continue, causing high cpu usage. how make conn.read() block call?

i've researched syscall package got stucked @ syscall.read() since found issue on os x 10.8.3 here source code related:

http://golang.org/src/pkg/syscall/zsyscall_darwin_amd64.go?h=read#l898

i have no idea syscall(sys_read, uintptr(fd), uintptr(_p0), uintptr(len(p))) means.

you're not handling tcp correctly. when conn.read() returns 0 bytes read, means peer has closed tcp connection gracefully. should close end of tcp connection in case.

(note not special go, read()/recv() returning 0 on tcp connection more or less universally means other end has closed connection)