HAProxy 严重减慢服务速度

Question

我认为我在 HAProxy 配置方面做错了，因为在使用 HAProxy 和一个 AWS 实例进行的实际测试中，我的吞吐量下降到了 25%。以下是我的相关（极其简单的）配置：

global
    log         127.0.0.1 local2
    chroot      /var/lib/haproxy
    pidfile     /var/run/haproxy.pid
    maxconn     20000
    user        haproxy
    group       haproxy
    daemon
    stats socket /var/lib/haproxy/stats
defaults
    mode                    http
    log                     global
    option                  httplog
    option                  dontlognull
    option http-server-close
    option forwardfor       except 127.0.0.0/8
    option                  redispatch
    retries                 3
    timeout http-request    10s
    timeout queue           1m

timeout connect         10s
    timeout client          1m
    timeout server          1m
    timeout http-keep-alive 10s
    timeout check           10s
    maxconn                 30000
frontend localnodes
    bind *:80
    mode http
    default_backend nodes
backend nodes
    mode http
    balance roundrobin
    hash-type consistent
    option httpchk /health
    server w1 xx.xx.xx.xx:80 check id 1

我已启用日志记录。日志中的典型条目如下所示：

Dec  2 10:56:59 localhost haproxy[25988]: xx.xx.xx.xx:39789 [02/Dec/2016:10:56:58.729] main app/app1 0/0/1000/1/1002 200 449 - - ---- 13/13/13/7/0 0/0 "GET / HTTP/1.1"
Dec  2 10:56:59 localhost haproxy[25988]: xx.xx.xx.xx:39803 [02/Dec/2016:10:56:58.730] main app/app1 0/0/999/1/1000 200 377 - - ---- 12/12/12/7/0 0/0 "GET / HTTP/1.1"
Dec  2 10:56:59 localhost haproxy[25988]: xx.xx.xx.xx:39804 [02/Dec/2016:10:56:58.730] main app/app1 0/0/999/1/1000 200 277 - - ---- 11/11/11/7/0 0/0 "GET / HTTP/1.1"

我的吞吐量只有实例直接流量的 25%。这性能太差了。我是不是做错了什么？