worker_processes 4;
worker_rlimit_nofile 40000;

events {
worker_connections 4096;
# accept_mutex on;
# accept_mutex_delay 500ms;
multi_accept on;
use epoll;
}

pm.max_children = 50
pm.start_servers = 4
pm.min_spare_servers = 4
pm.max_spare_servers = 32
pm.max_requests = 2500 //modified
rlimit_files = 131072 //modified
rlimit_core = unlimited //modified

# TCP Stack changes
net.ipv4.tcp_fin_timeout = 20
net.ipv4.tcp_tw_reuse = 1
net.core.netdev_max_backlog = 10000
net.core.somaxconn = 2048
net.ipv4.tcp_max_syn_backlog = 2048
net.ipv4.ip_local_port_range = 15000 65000

But still not efficient.
Losing visitors abnormally