From c3a3ac19f4eb8562b05a6dbb298d652d63f2ce75 Mon Sep 17 00:00:00 2001
From: Francis Bouvier <francis@lightpanda.io>
Date: Fri, 1 Nov 2024 17:54:49 +0100
Subject: [PATCH] server: set TCP.NODELAY on linux to avoid latency issues

Signed-off-by: Francis Bouvier <francis@lightpanda.io>
---
 src/main.zig | 24 ++++++++++++------------
 1 file changed, 12 insertions(+), 12 deletions(-)

diff --git a/src/main.zig b/src/main.zig
index 70ddb412..2bfe8c50 100644
--- a/src/main.zig
+++ b/src/main.zig
@@ -18,6 +18,7 @@
 
 const std = @import("std");
 const posix = std.posix;
+const builtin = @import("builtin");
 
 const jsruntime = @import("jsruntime");
 
@@ -99,6 +100,10 @@ pub const StreamServer = struct {
         self.* = undefined;
     }
 
+    fn setSockOpt(fd: posix.socket_t, level: i32, option: u32, value: c_int) !void {
+        try posix.setsockopt(fd, level, option, &std.mem.toBytes(value));
+    }
+
     pub fn listen(self: *StreamServer, address: std.net.Address) !void {
         const sock_flags = posix.SOCK.STREAM | posix.SOCK.CLOEXEC;
         var use_sock_flags: u32 = sock_flags;
@@ -112,21 +117,16 @@ pub const StreamServer = struct {
             self.sockfd = null;
         }
 
+        // socket options
         if (self.reuse_address) {
-            try posix.setsockopt(
-                sockfd,
-                posix.SOL.SOCKET,
-                posix.SO.REUSEADDR,
-                &std.mem.toBytes(@as(c_int, 1)),
-            );
+            try setSockOpt(sockfd, posix.SOL.SOCKET, posix.SO.REUSEADDR, 1);
         }
         if (@hasDecl(posix.SO, "REUSEPORT") and self.reuse_port) {
-            try posix.setsockopt(
-                sockfd,
-                posix.SOL.SOCKET,
-                posix.SO.REUSEPORT,
-                &std.mem.toBytes(@as(c_int, 1)),
-            );
+            try setSockOpt(sockfd, posix.SOL.SOCKET, posix.SO.REUSEPORT, 1);
+        }
+        if (builtin.target.os.tag == .linux) { // posix.TCP not available on MacOS
+            // WARNING: disable Nagle's alogrithm to avoid latency issues
+            try setSockOpt(sockfd, posix.IPPROTO.TCP, posix.TCP.NODELAY, 1);
         }
 
         var socklen = address.getOsSockLen();