Network Bandwidth testing or speed testing in python 2.7

Question

I am needing to test network bandwidth between a client and a server. I can do a simple drag and drop of the file and I get somewhere in the 800meg range according to the windows network monitor. The goal is to perform this same test using a python app, something like speedtest.net for inside the network. Here is the code I have been using but the results do not give me anything like I am seeing and I may just not understand them. The code comes from this site https://svn.python.org/projects/python/trunk/Demo/sockets/throughput.py

#! /usr/bin/env python

# Test network throughput.
#
# Usage:
# 1) on host_A: throughput -s [port]                    # start a server
# 2) on host_B: throughput -c  count host_A [port]      # start a client
#
# The server will service multiple clients until it is killed.
#
# The client performs one transfer of count*BUFSIZE bytes and
# measures the time it takes (roundtrip!).


import sys, time
from socket import *

MY_PORT = 50000 + 42

BUFSIZE = 1024


def main():
    if len(sys.argv) < 2:
        usage()
    if sys.argv[1] == '-s':
        server()
    elif sys.argv[1] == '-c':
        client()
    else:
        usage()


def usage():
    sys.stdout = sys.stderr
    print 'Usage:    (on host_A) throughput -s [port]'
    print 'and then: (on host_B) throughput -c count host_A [port]'
    sys.exit(2)


def server():
    if len(sys.argv) > 2:
        port = eval(sys.argv[2])
    else:
        port = MY_PORT
    s = socket(AF_INET, SOCK_STREAM)
    s.bind(('', port))
    s.listen(1)
    print 'Server ready...'
    while 1:
        conn, (host, remoteport) = s.accept()
        while 1:
            data = conn.recv(BUFSIZE)
            if not data:
                break
            del data
        conn.send('OK\n')
        conn.close()
        print 'Done with', host, 'port', remoteport


def client():
    if len(sys.argv) < 4:
        usage()
    count = int(eval(sys.argv[2]))
    host = sys.argv[3]
    if len(sys.argv) > 4:
        port = eval(sys.argv[4])
    else:
        port = MY_PORT
    testdata = 'x' * (BUFSIZE-1) + '\n'
    t1 = time.time()
    s = socket(AF_INET, SOCK_STREAM)
    t2 = time.time()
    s.connect((host, port))
    t3 = time.time()
    i = 0
    while i < count:
        i = i+1
        s.send(testdata)
    s.shutdown(1) # Send EOF
    t4 = time.time()
    data = s.recv(BUFSIZE)
    t5 = time.time()
    print data
    print 'Raw timers:', t1, t2, t3, t4, t5
    print 'Intervals:', t2-t1, t3-t2, t4-t3, t5-t4
    print 'Total:', t5-t1
    print 'Throughput:', round((BUFSIZE*count*0.001) / (t5-t1), 3),
    print 'K/sec.'


main()

Here is a sample output

OK
Raw timers: 1497614245.55 1497614245.55 1497614245.55 1497614268.85 1497614268.85
Intervals: 0.000999927520752 0.000999927520752 23.2929999828 0.00300002098083
Total: 23.2979998589
Throughput: 43952.271 K/sec.

Answer 1

I'm doing the similar test and looks like the result could be better if the size of test data is increased -- but still can't make use of the full available bandwidth (1Gbps in my case), don't know why.

For more detail, I was testing the bandwidth from a Win7 client to a Win7 server, If I changes the testdata to be 4 times of receiving buffer size, the network usage could be up to more than 80% on a 1Gbps link. If the testdata's size is similar with the buffer size, the usage would only be a little more than 30%.

When I do the test between a Debian8 client and the same Win7 server, the usage could be up to near 100%. Also, when I just copy a large file between the same Win7 machines through file sharing, it's also 100% usage. Looks like the problem lies in the client side. Any suggestion would be appreciated.

Code for server (Python3.6):

from __future__ import print_function

import datetime
import socket

HOST = '0.0.0.0'
PORT = 50000
BUFFER = 4096

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.bind((HOST,PORT))
sock.listen(0)
print('listening at %s:%s\n\r' %(HOST, PORT))

while True:
    client_sock, client_addr = sock.accept()

    starttime = datetime.datetime.now()
    print(starttime, end="")
    print('%s:%s connected\n\r' % client_addr)

    count = 0
    while True:
        data = client_sock.recv(BUFFER)
        if data:
            count += len(data)
            del data
            continue

        client_sock.close()

        endtime = datetime.datetime.now()
        print(endtime)
        print('%s:%s disconnected\n\r' % client_addr)

        print('bytes transferred: %d' % count)
        delta = endtime - starttime
        delta = delta.seconds + delta.microseconds / 1000000.0
        print('time used (seconds): %f' % delta)
        print('averaged speed (MB/s): %f\n\r' % (count / 1024 / 1024 / delta))
        break

sock.close()

Code for client (Python3.6):

import datetime
import socket

HOST = 'a.b.c.d'
PORT = 50000
BUFFER = 4096

testdata = b'x' * BUFFER * 4

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect((HOST,PORT))
for i in range(1, 1000000):
    sock.send(testdata)
sock.close()