requests distributed unevenly across multiple uwsgi child processes

[Davidrjx]

problem as following screenshoot,

almost all client requests processed by PID 8 above.

local uwsgi config

[uwsgi]
master = true
listen = 128
module = wsgi
http = :80
socket = /tmp/uwsgi.sock
add-header = Connection: Keep-Alive
http-keepalive = 65
chmod-socket = 666
processes = 3
threads = 1
disable-logging = true
buffer-size = 32768
enable-threads = true
socket-timeout = 600
harakiri = 600
lazy = true
logto = /tmp/uwsgi.log
log-maxsize = 5000000