姥爷自用 sysctl 文件分享：
vi /etc/sysctl.conf
fs.file-max = 65535
net.ipv4.tcp_slow_start_after_idle = 0
net.ipv4.tcp_mtu_probing = 1
vm.swappiness = 10
net.core.default_qdisc = fq
net.ipv4.tcp_congestion_control = bbr
sysctl -p
详细分析请见下面博文：
https://1kb.day/posts/linux_sysctl.html
