NGINX / PHP-FPM + SSL очень медленно

Мое приложение обслуживается на экземпляре Amazon EC2 t2.small.

При использовании команды ab для проверки производительности.

] ab -n 3000 -c 100 mydomain.com

HTTP

Finished 3000 requests


Server Software:        nginx/1.8.1
Server Hostname:        www.mydomain.com
Server Port:            80

Document Path:          /
Document Length:        184 bytes

Concurrency Level:      100
Time taken for tests:   3.201 seconds
Complete requests:      3000
Failed requests:        0
Non-2xx responses:      3000
Total transferred:      1401000 bytes
HTML transferred:       552000 bytes
Requests per second:    937.09 [#/sec] (mean)
Time per request:       106.714 [ms] (mean)
Time per request:       1.067 [ms] (mean, across all concurrent requests)
Transfer rate:          427.36 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:       15   43  50.0     33     783
Processing:    19   53  79.2     37    1437
Waiting:       17   47  75.1     34    1437
Total:         41   96  93.3     71    1463

Percentage of the requests served within a certain time (ms)
  50%     71
  66%     79
  75%     85
  80%     91
  90%    160
  95%    175
  98%    478
  99%    573
 100%   1463 (longest request)

HTTPS

Finished 3000 requests


Server Software:        nginx/1.8.1
Server Hostname:        www.mydomain.com
Server Port:            443
SSL/TLS Protocol:       TLSv1.2,ECDHE-RSA-AES256-GCM-SHA384,1024,256

Document Path:          /
Document Length:        212 bytes

Concurrency Level:      100
Time taken for tests:   23.034 seconds
Complete requests:      3000
Failed requests:        124
   (Connect: 0, Receive: 0, Length: 124, Exceptions: 0)
Non-2xx responses:      2876
Total transferred:      21357330 bytes
HTML transferred:       20773030 bytes
Requests per second:    130.24 [#/sec] (mean)
Time per request:       767.790 [ms] (mean)
Time per request:       7.678 [ms] (mean, across all concurrent requests)
Transfer rate:          905.49 [Kbytes/sec] received

Connection Times (ms)
              min  mean[+/-sd] median   max
Connect:      105  521 170.7    584     892
Processing:    20  228 264.1    153    2629
Waiting:       17  149 131.1    111     772
Total:        201  749 214.4    714    3124

Percentage of the requests served within a certain time (ms)
  50%    714
  66%    740
  75%    745
  80%    755
  90%    798
  95%    903
  98%   1484
  99%   2002
 100%   3124 (longest request)

Релевантные части моего nginx.conf:

user                 ec2-user ec2-user;
worker_processes     4;

error_log            /home/ec2-user/.log/error.log error;
pid                  /var/run/nginx.pid;

#timer_resolution    500ms;
worker_rlimit_nofile 8192;

events {
  worker_connections 4096;
}

http {
  include       /etc/nginx/mime.types;
  default_type  application/octet-stream;
  autoindex     off;

  index index.php index.html index.htm;

  sendfile           on;
  tcp_nopush         on;
  tcp_nodelay        off;
  keepalive_timeout  60;
  keepalive_requests 10;

  client_max_body_size      20M;
  client_body_timeout       60;
  client_body_buffer_size   10M;
  client_header_timeout     60;
  client_header_buffer_size 1k;

  #server_names_hash_max_size    512;
  server_names_hash_bucket_size 128;

  gzip              on;
  gzip_disable      "msie6";
  gzip_vary         on;
  gzip_proxied      any;
  gzip_comp_level   6;
  gzip_buffers      16 8k;
  gzip_http_version 1.1;
  gzip_min_length   1000;
  gzip_types        text/plain text/css application/json application/x-javascript text/xml application/xml application/rss+xml text/javascript image/svg+xml application/vnd.ms-fontobject application/x-font-ttf font/opentype;
}

и mydomain.conf

ssl                       on;
ssl_session_timeout       5m;
ssl_protocols             TLSv1 TLSv1.1 TLSv1.2;
ssl_ciphers               ECDHE-RSA-AES256-GCM-SHA384:ECDHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384:DHE-RSA-AES128-GCM-SHA256:ECDHE-RSA-AES256-SHA384:ECDHE-RSA-AES128-SHA256:ECDHE-RSA-AES256-SHA:ECDHE-RSA-AES128-SHA:DHE-RSA-AES256-SHA256:DHE-RSA-AES128-SHA256:DHE-RSA-AES256-SHA:DHE-RSA-AES128-SHA:ECDHE-RSA-DES-CBC3-SHA:EDH-RSA-DES-CBC3-SHA:AES256-GCM-SHA384:AES128-GCM-SHA256:AES256-SHA256:AES128-SHA256:AES256-SHA:AES128-SHA:DES-CBC3-SHA:HIGH:!aNULL:!eNULL:!EXPORT:!DES:!MD5:!PSK:!RC4;
ssl_prefer_server_ciphers on;
ssl_dhparam               /home/ec2-user/.nginx/dhparam.pem;

ssl_stapling              on;
ssl_stapling_verify       on;

resolver                  8.8.4.4 8.8.8.8 valid=300s;
resolver_timeout          10s;

add_header                Strict-Transport-Security max-age=63072000;
add_header                X-Content-Type-Options    nosniff;