Airflow webserver responses slow intermittently

[Jason Chen]

Hi airflow team,
 I am using airflow v1.7.1.3 (gunicorn 19.3.0)

 It seems airflow webserver responses slow intermittently.
 It sometimes takes time to just go to the home page of airflow DAG UI.

I tried to start webserver in debug mode (`airflow webserver -d`) and can
see the client/UI requests. not saw unusual messages in debug mode though.

 Any suggestions ?

 Thanks.

-Jason

 Note scheduler is running, just webserver is slow. We only have one DAG.

BTW, in the webserver log, we see following messages sometimes (not having
such messages when webserver responses slow though).


[2016-09-01 04:54:43 +0000] [14158] [ERROR] Socket error processing request.
Traceback (most recent call last):
  File "/usr/local/lib/python2.7/site-packages/gunicorn/workers/sync.py",
line 129, in handle
    req = six.next(parser)
  File "/usr/local/lib/python2.7/site-packages/gunicorn/http/parser.py",
line 41, in __next__
    self.mesg = self.mesg_class(self.cfg, self.unreader, self.req_count)
  File "/usr/local/lib/python2.7/site-packages/gunicorn/http/message.py",
line 153, in __init__
    super(Request, self).__init__(cfg, unreader)
  File "/usr/local/lib/python2.7/site-packages/gunicorn/http/message.py",
line 53, in __init__
    unused = self.parse(self.unreader)
  File "/usr/local/lib/python2.7/site-packages/gunicorn/http/message.py",
line 165, in parse
    self.get_data(unreader, buf, stop=True)
  File "/usr/local/lib/python2.7/site-packages/gunicorn/http/message.py",
line 156, in get_data
    data = unreader.read()
  File "/usr/local/lib/python2.7/site-packages/gunicorn/http/unreader.py",
line 38, in read
    d = self.chunk()
  File "/usr/local/lib/python2.7/site-packages/gunicorn/http/unreader.py",
line 65, in chunk
    return self.sock.recv(self.mxchunk)
error: [Errno 4] Interrupted system call