tcp_notsent_lowat

 TCP_NOTSENT_LOWAT

更改 tcp_notsent_lowat 为 16384（16K）可以优化 web 速度。

#添加值
echo "net.ipv4.tcp_notsent_lowat = 16384" >> /etc/sysctl.conf

#查看是否成功
sysctl net.ipv4.tcp_notsent_lowat

    TCP_NOTSENT_LOWAT      The send socket buffer of a TCP sender has unsent
                            and unacknowledged data. This option allows a TCP
                            sender to control the amount of unsent data kept
                            in the send socket buffer. The value of the option
                            should be the maximum amount of unsent data in
                            bytes. Kevent, poll and select will generate a
                            write notification when the unsent data falls
                            below the amount given by this option. This will
                            allow an application to generate just-in-time
                            fresh updates for real-time communication.