Measuring RTT and retrieve time between a sensor and a platform

Question

Suppose we have a platform for receiving data from a sensor. We show the measuring time for sending a data value from a sensor to the platform with TR (retrieve time). All I want is what code can be used to calculate TR and also RTT (round trip time) in Python.

Answer 1

You didn't mention specifics such latency threshold and protocol. I think your best bet is to setup a client/server ping/pong server.

Here is some simple zeromq python code (Request/Reply pattern) to test latency (single trip and round trip)

server.py

import zmq,time,sys

ctx =zmq.Context()
socket = ctx.socket(zmq.REP)
socket.bind('tcp://*:9999')

while True:
    msg = socket.recv()
    print "client->server msg took",time.time()-float(msg)
    socket.send(msg)

client.py

import zmq,time,sys                                                                                                                        

ctx =zmq.Context()                                                                                                                         
socket = ctx.socket(zmq.REQ)                                                                                                               
socket.connect('tcp://localhost:9999')                                                                                                     
for i in xrange(10):                                                                                                                       
    socket.send(str(time.time()))                                                                                                          
    msg = socket.recv()                                                                                                                    
    print "message id",i,"RT",time.time()-float(msg)    

You can run both of them the same time to give you latency stats. Is this what you are looking for?