performance moduleΒΆ

#!/usr/bin/env python
"""
Pymodbus Performance Example
--------------------------------------------------------------------------

The following is an quick performance check of the synchronous
modbus client.
"""
# --------------------------------------------------------------------------- # 
# import the necessary modules
# --------------------------------------------------------------------------- #
from __future__ import print_function
import logging, os
from time import time
# from pymodbus.client.sync import ModbusTcpClient
from pymodbus.client.sync import ModbusSerialClient

try:
    from multiprocessing import log_to_stderr
except ImportError:
    import logging
    logging.basicConfig()
    log_to_stderr = logging.getLogger

# --------------------------------------------------------------------------- # 
# choose between threads or processes
# --------------------------------------------------------------------------- # 

#from multiprocessing import Process as Worker
from threading import Thread as Worker
from threading import Lock
_thread_lock = Lock()
# --------------------------------------------------------------------------- # 
# initialize the test
# --------------------------------------------------------------------------- # 
# Modify the parameters below to control how we are testing the client:
#
# * workers - the number of workers to use at once
# * cycles  - the total number of requests to send
# * host    - the host to send the requests to
# --------------------------------------------------------------------------- # 
workers = 10
cycles = 1000
host = '127.0.0.1'


# --------------------------------------------------------------------------- # 
# perform the test
# --------------------------------------------------------------------------- # 
# This test is written such that it can be used by many threads of processes
# although it should be noted that there are performance penalties
# associated with each strategy.
# --------------------------------------------------------------------------- # 
def single_client_test(host, cycles):
    """ Performs a single threaded test of a synchronous
    client against the specified host

    :param host: The host to connect to
    :param cycles: The number of iterations to perform
    """
    logger = log_to_stderr()
    logger.setLevel(logging.DEBUG)
    logger.debug("starting worker: %d" % os.getpid())

    try:
        count = 0
        # client = ModbusTcpClient(host, port=5020)
        client = ModbusSerialClient(method="rtu",
                                    port="/dev/ttyp0", baudrate=9600)
        while count < cycles:
            with _thread_lock:
                client.read_holding_registers(10, 1, unit=1).registers[0]
                count += 1
    except:
        logger.exception("failed to run test successfully")
    logger.debug("finished worker: %d" % os.getpid())

# --------------------------------------------------------------------------- # 
# run our test and check results
# --------------------------------------------------------------------------- # 
# We shard the total number of requests to perform between the number of
# threads that was specified. We then start all the threads and block on
# them to finish. This may need to switch to another mechanism to signal
# finished as the process/thread start up/shut down may skew the test a bit.

# RTU 32 requests/second @9600
# TCP 31430 requests/second

# --------------------------------------------------------------------------- #


if __name__ == "__main__":
    args = (host, int(cycles * 1.0 / workers))
    procs = [Worker(target=single_client_test, args=args)
             for _ in range(workers)]
    start = time()
    any(p.start() for p in procs)   # start the workers
    any(p.join() for p in procs)   # wait for the workers to finish
    stop = time()
    print("%d requests/second" % ((1.0 * cycles) / (stop - start)))
    print("time taken to complete %s cycle by "
          "%s workers is %s seconds" % (cycles, workers, stop-start))