From 8224c3e8bfb163d8e2b0fa5c731856ce5973d524 Mon Sep 17 00:00:00 2001
From: Joway <joway.w@gmail.com>
Date: Thu, 9 Sep 2021 18:50:33 +0800
Subject: [PATCH] feat: support TCP_NODELAY (#39)

* feat: support TCP_NODELAY

* feat: default tcp_nodelay = true

* feat: hide intertal interface

* chore: fix tests
---
 connection_impl.go   |  5 +++++
 connection_test.go   | 14 ++++++++++++++
 go.sum               |  2 --
 sys_exec.go          | 13 +++++++++++++
 sys_sockopt_linux.go |  8 --------
 5 files changed, 32 insertions(+), 10 deletions(-)

diff --git a/connection_impl.go b/connection_impl.go
index 09d55608..a7494337 100644
--- a/connection_impl.go
+++ b/connection_impl.go
@@ -264,6 +264,11 @@ func (c *connection) init(conn Conn, prepare OnPrepare) (err error) {
 	c.inputBarrier, c.outputBarrier = barrierPool.Get().(*barrier), barrierPool.Get().(*barrier)
 	c.setFinalizer()
 
+	// enable TCP_NODELAY by default
+	switch c.network {
+	case "tcp", "tcp4", "tcp6":
+		setTCPNoDelay(c.fd, true)
+	}
 	// check zero-copy
 	if setZeroCopy(c.fd) == nil && setBlockZeroCopySend(c.fd, defaultZeroCopyTimeoutSec, 0) == nil {
 		c.supportZeroCopy = true
diff --git a/connection_test.go b/connection_test.go
index 1a078ca2..ea785ada 100644
--- a/connection_test.go
+++ b/connection_test.go
@@ -233,3 +233,17 @@ func TestConnectionLargeMemory(t *testing.T) {
 		panic(fmt.Sprintf("alloc[%d] out of memory %d", alloc, limit))
 	}
 }
+
+// TestSetTCPNoDelay is used to verify the connection initialization set the TCP_NODELAY correctly
+func TestSetTCPNoDelay(t *testing.T) {
+	fd, err := sysSocket(syscall.AF_INET, syscall.SOCK_STREAM, 0)
+	conn := &connection{}
+	conn.init(&netFD{network: "tcp", fd: fd}, nil)
+
+	n, _ := syscall.GetsockoptInt(fd, syscall.IPPROTO_TCP, syscall.TCP_NODELAY)
+	MustTrue(t, n > 0)
+	err = setTCPNoDelay(fd, false)
+	MustNil(t, err)
+	n, _ = syscall.GetsockoptInt(fd, syscall.IPPROTO_TCP, syscall.TCP_NODELAY)
+	MustTrue(t, n == 0)
+}
diff --git a/go.sum b/go.sum
index c022ebc3..7618b6e9 100644
--- a/go.sum
+++ b/go.sum
@@ -1,5 +1,3 @@
-github.com/bytedance/gopkg v0.0.0-20210507130052-24980f04837a h1:wjM2Z8ZV1OjQMyVSoXIDqjWK5BEuRHT+S6kLH1BVR5c=
-github.com/bytedance/gopkg v0.0.0-20210507130052-24980f04837a/go.mod h1:birsdqRCbwnckJbdAvcSao+AzOyibVEoWB55MjpYpB8=
 github.com/bytedance/gopkg v0.0.0-20210705062217-74c74ebadcae h1:ERLYTdHnm2E8jwpprhHPvBhbPBaxnwl62tb3lR8Nd+k=
 github.com/bytedance/gopkg v0.0.0-20210705062217-74c74ebadcae/go.mod h1:birsdqRCbwnckJbdAvcSao+AzOyibVEoWB55MjpYpB8=
 github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8=
diff --git a/sys_exec.go b/sys_exec.go
index 224f3367..33122adf 100644
--- a/sys_exec.go
+++ b/sys_exec.go
@@ -28,6 +28,11 @@ func GetSysFdPairs() (r, w int) {
 	return fds[0], fds[1]
 }
 
+// setTCPNoDelay set the TCP_NODELAY flag on socket
+func setTCPNoDelay(fd int, b bool) (err error) {
+	return syscall.SetsockoptInt(fd, syscall.IPPROTO_TCP, syscall.TCP_NODELAY, boolint(b))
+}
+
 // Wrapper around the socket system call that marks the returned file
 // descriptor as nonblocking and close-on-exec.
 func sysSocket(family, sotype, proto int) (int, error) {
@@ -101,3 +106,11 @@ func iovecs(bs [][]byte, ivs []syscall.Iovec) (iovLen int) {
 	}
 	return iovLen
 }
+
+// Boolean to int.
+func boolint(b bool) int {
+	if b {
+		return 1
+	}
+	return 0
+}
diff --git a/sys_sockopt_linux.go b/sys_sockopt_linux.go
index def023bd..5a7dddce 100644
--- a/sys_sockopt_linux.go
+++ b/sys_sockopt_linux.go
@@ -23,11 +23,3 @@ func setDefaultSockopts(s, family, sotype int, ipv6only bool) error {
 	// Allow broadcast.
 	return os.NewSyscallError("setsockopt", syscall.SetsockoptInt(s, syscall.SOL_SOCKET, syscall.SO_BROADCAST, 1))
 }
-
-// Boolean to int.
-func boolint(b bool) int {
-	if b {
-		return 1
-	}
-	return 0
-}