pounder_test/scripts/stream_throughput.py

190 lines
4.8 KiB
Python
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2021-06-15 19:18:16 +08:00
#!/usr/bin/python3
"""
Author: Ryan Summers
Description: Provides a mechanism for measuring Stabilizer stream data throughput.
"""
import socket
import collections
import struct
import time
import logging
# Representation of a single UDP packet transmitted by Stabilizer.
Packet = collections.namedtuple('Packet', ['index', 'adc', 'dac'])
class Timer:
""" A basic timer for measuring elapsed time periods. """
def __init__(self, period=1.0):
""" Create the timer with the provided period. """
self.start_time = time.time()
self.trigger_time = self.start_time + period
self.period = period
self.started = False
def is_triggered(self):
""" Check if the timer period has elapsed. """
now = time.time()
return now >= self.trigger_time
def start(self):
""" Start the timer. """
self.start_time = time.time()
self.started = True
def is_started(self):
""" Check if the timer has started. """
return self.started
def arm(self):
""" Arm the timer trigger. """
self.trigger_time = time.time() + self.period
def elapsed(self):
""" Get the elapsed time since the timer was started. """
now = time.time()
return now - self.start_time
class PacketParser:
""" Utilize class used for parsing received UDP data. """
def __init__(self):
""" Initialize the parser. """
self.buf = b''
self.total_bytes = 0
def ingress(self, data):
""" Ingress received UDP data. """
self.total_bytes += len(data)
self.buf += data
def parse_all_packets(self):
""" Parse all received packets from the receive buffer.
Returns:
A list of received Packets.
"""
packets = []
while True:
new_packets = self._parse()
if new_packets:
packets += new_packets
else:
return packets
def _parse(self):
""" Attempt to parse packets from the received buffer. """
# Attempt to parse a block from the buffer.
if len(self.buf) < 4:
return None
start_id, num_blocks, data_size = struct.unpack_from('!HBB', self.buf)
packet_size = 4 + data_size * num_blocks * 8
if len(self.buf) < packet_size:
return None
self.buf = self.buf[4:]
packets = []
for offset in range(num_blocks):
adcs_dacs = struct.unpack_from(f'!{4 * data_size}H', self.buf)
adc = [
adcs_dacs[0:data_size],
adcs_dacs[data_size:2*data_size],
]
dac = [
adcs_dacs[2*data_size: 3*data_size],
adcs_dacs[3*data_size:],
]
self.buf = self.buf[8*data_size:]
packets.append(Packet(start_id + offset, adc, dac))
return packets
def check_index(previous_index, next_index):
""" Check if two indices are sequential. """
if previous_index == -1:
return True
# Handle index roll-over. Indices are only stored in 16-bit numbers.
if next_index < previous_index:
next_index += 65536
expected_index = previous_index + 1
return next_index == expected_index
def main():
""" Main program. """
connection = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
connection.bind(("", 1111))
logging.basicConfig(level=logging.INFO,
format='%(asctime)s.%(msecs)03d %(levelname)-8s %(message)s')
last_index = -1
drop_count = 0
good_blocks = 0
timer = Timer()
parser = PacketParser()
while True:
# Receive any data over UDP and parse it.
data = connection.recv(4096)
if data and not timer.is_started():
timer.start()
parser.ingress(data)
# Handle any received packets.
for packet in parser.parse_all_packets():
# Handle any dropped packets.
if not check_index(last_index, packet.index):
print(hex(last_index), hex(packet.index))
if packet.index < (last_index + 1):
dropped = packet.index + 65536 - (last_index + 1)
else:
dropped = packet.index - (last_index + 1)
drop_count += dropped
last_index = packet.index
good_blocks += 1
# Report the throughput periodically.
if timer.is_triggered():
drate = parser.total_bytes * 8 / 1e6 / timer.elapsed()
print(f'''
Data Rate: {drate:.3f} Mbps
Received Blocks: {good_blocks}
Dropped blocks: {drop_count}
Metadata: {parser.total_bytes / 1e6:.3f} MB in {timer.elapsed():.2f} s
----
''')
timer.arm()
if __name__ == '__main__':
main()