$ git clone 
$ cd bilitw
$ autoreconf -fvi
$ ./configure  CFLAGS="-DGRACEFUL -g -O2" --enable-debug=full
$ make
$ make install
$ nohup bilitw -o /var/log/bilitw.log  -v 3 &

stats_duration indicates the interval of statistics printout in log file.   
default: 300000 milliseconds -> 5 minutes.

reload_timeout indicates the timeout for graceful reload, if the timeout reached, old workers will close the client connection.  
default: 120000 milliseconds -> 2 minutes

slow_req_duration is the timeout for slow request value
slow request is the response of redis/memcached exceeds slow_req_duration timeout.  
default: not set by default

global:
 stats_duration: 600000
 reload_timeout: 60000
 slow_req_duration: 5000
 stats_file: /tmp/twstats.log

alpha:
 listen: 127.0.0.1:22121
 slow_req_duration: 3000
 hash: fnv1a_64
 distribution: ketama
 auto_eject_hosts: true
 redis: true
 server_retry_timeout: 2000
 server_failure_limit: 1
 servers:
  - 127.0.0.1:6379:1 myserver
  - 127.0.0.1:6380:1 myserver1

localhost:~:# ps -ef | grep bilitw
root     19521 19227  0 19:22 pts/0    00:00:00 bilitw master
root     19522 19521  0 19:22 pts/0    00:00:00 bilitw worker 0
root     19523 19521  0 19:22 pts/0    00:00:00 bilitw worker 1
kill -SIGHUP 19521

$ bilitw -h
Options:
-h, --help             : this help
-V, --version          : show version and exit
-t, --test-conf        : test configuration for syntax errors and exit
-d, --daemonize        : run as a daemon
-D, --describe-stats   : print stats description and exit
-v, --verbose=N        : set logging level (default: 5, min: 0, max: 11)
-o, --output=S         : set logging file (default: stderr)
-c, --conf-file=S      : set configuration file (default: /etc/nutcracker.yml)
-s, --stats-port=N     : set stats monitoring port (default: 22223)
-a, --stats-addr=S     : set stats monitoring ip (default: 0.0.0.0)
-i, --stats-interval=N : set stats aggregation interval in msec (default: 30000 msec)
-p, --pid-file=S       : set pid file (default: off)
-m, --mbuf-size=N      : set size of mbuf chunk in bytes (default: 16384 bytes)
-n, --worker-num=N     : set number of workers (default: number of cpu cores)
-M, --core-mask=N      : set cpu core mask that worker process bind to

bilitw -n 2 -M 12    
// 2 means launch 2 workers
// 12 means mask bitmap 0x1100, which tell 2 workers to bind on cpu 2 and cpu 3. 

localhost:~:# ps -ef | grep bilitw
root     19521 19227  0 19:22 pts/0    00:00:00 bilitw master
root     19522 19521  0 19:22 pts/0    00:00:00 bilitw worker 0
root     19523 19521  0 19:22 pts/0    00:00:00 bilitw worker 1

[2015-12-21 19:20:15.247] nc_process.c:256 set worker 0 affinity to cpu core 2
[2015-12-21 19:20:15.247] nc_process.c:256 set worker 1 affinity to cpu core 3

$ bilitw --describe-stats

pool stats:
  client_eof          "# eof on client connections"
  client_err          "# errors on client connections"
  client_connections  "# active client connections"
  server_ejects       "# times backend server was ejected"
  forward_error       "# times we encountered a forwarding error"
  fragments           "# fragments created from a multi-vector request"

server stats:
  server_eof          "# eof on server connections"
  server_err          "# errors on server connections"
  server_timedout     "# timeouts on server connections"
  server_connections  "# active server connections"
  requests            "# requests"
  request_bytes       "total request bytes"
  responses           "# responses"
  response_bytes      "total response bytes"
  in_queue            "# requests in incoming queue"
  in_queue_bytes      "current request bytes in incoming queue"
  out_queue           "# requests in outgoing queue"
  out_queue_bytes     "current request bytes in outgoing queue"