low baudrate output #89
Description
Describe the bug
When writing to the BLE serial i can only read ~200 byes/s, while when reading i can easily get over 50.000B/s (and my BT firmware seems to be the bottleneck
Log messages
I use a python script with pyserial, ser1.write(data) where data is 512 bytes (MTU exchanges is 247 and from my smartphone i can exceed 110.000 B/s).
I can see a virtual output speed of 72MB/s for write, but seems like this data is parked in a buffer that then get flushed WAY slower:
17:00:47.935 | DEBUG | ble_interface.py: Sending b'nnnnnnnnoooooooooopp'
17:00:48.025 | DEBUG | ble_interface.py: Sending b'ppppppppqqqqqqqqqqrr'
17:00:48.118 | DEBUG | ble_interface.py: Sending b'rrrrrrrrsssssssssstt'
17:00:48.208 | DEBUG | ble_interface.py: Sending b'ttttttttuuuuuuuuuuvv'
17:00:48.295 | DEBUG | ble_interface.py: Sending b'vvvvvvvvzzzzzzzzzzyy'
17:00:48.385 | DEBUG | ble_interface.py: Sending b'yyyyyyyy000000000011
Noticing the potential huge amount of data getting buffred may be the issue, i put delay between write, to force the bitrate to remain around 921600 (my target), and it did not work
I find interesting the library is sending way less data than it should per packet that it should (~20 instead of 247, that sound like the standard MTU)
and way less packet/s than it should (10Hz instead of 500Hz)
Setup (please complete the following information):
- OS: Arch
- Bluetooth Hardware: ID 2550:8761 Realtek Bluetooth Radio
- BlueZ Version: 5.70
- Python Version: 3.11.5
- ble-serial and dependency versions:
ble-serial 2.7.1
bleak 0.21.1
coloredlogs 15.0.1
dbus-fast 2.11.1
humanfriendly 10.0
pip 23.2.1
setuptools 65.5.0
typing_extensions 4.8.0
Additional Context
full test code:
#!/usr/bin/python
import serial
import time
import os
import sys
data = b'aaaaaaaaaabbbbbbbbbbccccccccccddddddddddeeeeeeeeeeffffffffffgggggggggghhhhhhhhhhiiiiiiiiiillllllllllmmmmmmmmmmnnnnnnnnnnooooooooooppppppppppqqqqqqqqqqrrrrrrrrrrssssssssssttttttttttuuuuuuuuuuvvvvvvvvvvzzzzzzzzzzyyyyyyyyyy000000000011111111112222222222\r\n3333333333444444444455555555556666666666777777777788888888889999999999!!!!!!!!!!@@@@@@@@@@##########$$$$$$$$$$%%%%%%%%%%^^^^^^^^^^&&&&&&&&&&**********(((((((((())))))))))__________++++++++++==========]]]]]]]]]]{{{{{{{{{{""""""""""..........,,,,,,,,,,\r\n'
ser1 = serial.Serial(sys.argv[1], timeout=0.1, baudrate=int(sys.argv[2]))
ser2 = serial.Serial(sys.argv[3], timeout=0.1, baudrate=int(sys.argv[4]))
data_out = 0
data_in = 0
check_index = 0
correct = 0
loops = 0
while True:
loops += 1
start = time.time()
print(f"writing {len(data)}")
complete = False
ser1.write(data)
data_out += len(data)
duration = time.time() - start
print(f"data out: {data_out} data in: {data_in}, correct {correct} B/s: {len(data) / duration} {len(data)} {loops}")
time.sleep(0.0054-duration)
duration = time.time() - start
print(f"B/s: {len(data) / duration}")
print("end")
edit:
on reception, the library seems to work ok. I can generate 120.000/150.000 bytes/s (confirmed on android smartphone with blueftuit) and i can receive 80.000 on PC with this library (antenna on the pc is not optimal placed) both using TCP and SERIAL mode.
Also tested the TCP mode foroutput, and i got the 200bytes/s max too.