How to reduce the latency overheads of Nginx as load balancer

[bj]

Hello,

I am using Nginx as my load balancer to Apache backend servers. It works
great.  

But I experienced a significant latency overhead Nginx  load balancer
added  under heavy loaded traffics.   I noticed that the response time
increased from 1.5 sec to 3.0 sec, when compared with the case that no
Nginx is used.

Do you have any suggestions on how I should configure Nginx to reduce
such latency overheads?
My Nginx configuration is attached below for your info.

Thanks,
Chang


==========================================
     My Nginx configuration file
==========================================

worker_rlimit_nofile 65536;
worker_processes 4;

events {
    worker_connections 8182;
    use epoll;
}
http {
    server_names_hash_bucket_size 64;
    include /usr/local/nginx/conf/mime.types;
    default_type application/octet-stream;
    sendfile on;
    tcp_nopush on;
    keepalive_timeout 65;
    tcp_nodelay on;
    fastcgi_read_timeout 180;
    gzip on;
    gzip_min_length 1100;
    gzip_buffers 4 8k;
    gzip_types text/plain;
    upstream backend_10_1{
        server 192.168.2.110:80; server 192.168.2.111:80; server
192.168.2.112:80;
    }

    server {
        server_name default;
        listen 10.20.131.14;
        error_log /dev/null crit;
        access_log off;
        rewrite_log off;
        location / {
            proxy_pass         http://backend_10_1;
            proxy_redirect     off;
            proxy_buffering    off;
            proxy_set_header   Host             $host;
            proxy_set_header   X-Real-IP        $remote_addr;
            proxy_set_header   X-Forwarded-For 
$proxy_add_x_forwarded_for;
        }
    }
}

Posted at Nginx Forum: http://forum.nginx.org/read.php?2,117965,117965#msg-117965