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Python host optimizations (bytes_to_hexstr, log formatting, _now_ms) #56

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Python host optimizations (bytes_to_hexstr, log formatting, _now_ms) #56

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a031c1b
perf(host): speed up bytes_to_hexstr up to 100x
lukasnee Mar 3, 2025
8c227e1
perf(host): avoid bytes_to_hexstr formatting when not needed
lukasnee Mar 3, 2025
6f09169
perf(host): avoid unnecessary calls to relatively expensive _now_ms
lukasnee Mar 3, 2025
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62 changes: 34 additions & 28 deletions host/min.py
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Original file line number Diff line number Diff line change
Expand Up @@ -11,7 +11,7 @@
from binascii import crc32
from threading import Lock
from time import time
from logging import getLogger, ERROR
from logging import getLogger, ERROR, DEBUG, INFO
from typing import Dict, Optional, List

from serial import Serial, SerialException
Expand All @@ -28,7 +28,7 @@ def int32_to_bytes(value: int) -> bytes:


def bytes_to_hexstr(bytesequence: bytes) -> str:
return "".join(f"{b:02X}" for b in bytesequence)
return bytesequence.hex().upper()


class MINConnectionError(Exception):
Expand Down Expand Up @@ -254,14 +254,16 @@ def send_frame(self, min_id: int, payload: bytes):
raise ValueError("MIN ID out of range")
frame = MINFrame(min_id=min_id, payload=payload, transport=False, seq=0)
on_wire_bytes = self._on_wire_bytes(frame=frame)
min_logger.info(
"Sending MIN frame, min_id=0x%02X, payload=%s",
min_id,
bytes_to_hexstr(payload),
)
min_logger.debug(
"Sending MIN frame, on wire bytes=%s", bytes_to_hexstr(on_wire_bytes)
)
if min_logger.isEnabledFor(INFO):
min_logger.info(
"Sending MIN frame, min_id=0x%02X, payload=%s",
min_id,
bytes_to_hexstr(payload),
)
if min_logger.isEnabledFor(DEBUG):
min_logger.debug(
"Sending MIN frame, on wire bytes=%s", bytes_to_hexstr(on_wire_bytes)
)
self._serial_write(on_wire_bytes)

def queue_frame(self, min_id: int, payload: bytes):
Expand Down Expand Up @@ -485,7 +487,8 @@ def _rx_bytes(self, data: bytes):
Called by handler to pass over a sequence of bytes
:param data:
"""
min_logger.debug("Received bytes: %s", bytes_to_hexstr(data))
if min_logger.isEnabledFor(DEBUG):
min_logger.debug("Received bytes: %s", bytes_to_hexstr(data))
for byte in data:
if self._rx_header_bytes_seen == 2:
self._rx_header_bytes_seen = 0
Expand Down Expand Up @@ -660,12 +663,13 @@ def _find_oldest_frame(self):
if len(self._transport_fifo) == 0:
raise AssertionError

now_ms = self._now_ms()
window_size = (self._sn_max - self._sn_min) & 0xFF
oldest_frame = self._transport_fifo[0] # type: MINFrame
longest_elapsed_time = self._now_ms() - oldest_frame.last_sent_time
longest_elapsed_time = now_ms - oldest_frame.last_sent_time

for i in range(window_size):
elapsed = self._now_ms() - self._transport_fifo[i].last_sent_time
elapsed = now_ms - self._transport_fifo[i].last_sent_time
if elapsed >= longest_elapsed_time:
oldest_frame = self._transport_fifo[i]
longest_elapsed_time = elapsed
Expand All @@ -680,11 +684,12 @@ def poll(self):

:return: array of accepted MIN frames
"""
now_ms = self._now_ms()
remote_connected = (
self._now_ms() - self._last_received_anything_ms
now_ms - self._last_received_anything_ms
) < self.idle_timeout_ms
remote_active = (
self._now_ms() - self._last_received_frame_ms
now_ms - self._last_received_frame_ms
) < self.idle_timeout_ms

self._rx_list = []
Expand All @@ -701,23 +706,24 @@ def poll(self):
# Frames still to send
frame = self._transport_fifo_get(n=window_size)
frame.seq = self._sn_max
self._last_sent_frame_ms = self._now_ms()
frame.last_sent_time = self._now_ms()
min_logger.debug(
"Sending new frame id=0x%02X seq=%d len=%d payload=%s",
frame.min_id,
frame.seq,
len(frame.payload),
bytes_to_hexstr(frame.payload),
)
self._last_sent_frame_ms = now_ms
frame.last_sent_time = now_ms
if min_logger.isEnabledFor(DEBUG):
min_logger.debug(
"Sending new frame id=0x%02X seq=%d len=%d payload=%s",
frame.min_id,
frame.seq,
len(frame.payload),
bytes_to_hexstr(frame.payload),
)
self._transport_fifo_send(frame=frame)
self._sn_max = (self._sn_max + 1) & 0xFF
else:
# Maybe retransmits
if window_size > 0 and remote_connected:
oldest_frame = self._find_oldest_frame()
if (
self._now_ms() - oldest_frame.last_sent_time
now_ms - oldest_frame.last_sent_time
> self.frame_retransmit_timeout_ms
):
min_logger.debug(
Expand All @@ -729,7 +735,7 @@ def poll(self):

# Periodically transmit ACK
if (
self._now_ms() - self._last_sent_ack_time_ms
now_ms - self._last_sent_ack_time_ms
> self.ack_retransmit_timeout_ms
):
if remote_active:
Expand Down Expand Up @@ -777,8 +783,8 @@ def _now_ms(self):
def _serial_write(self, data: bytes):
if self.fake_errors:
data = self._corrupted_data(data)

min_logger.debug("_serial_write: %s", bytes_to_hexstr(data))
if min_logger.isEnabledFor(DEBUG):
min_logger.debug("_serial_write: %s", bytes_to_hexstr(data))
self._serial.write(data)

def _serial_any(self):
Expand Down