#!/usr/bin/env python3 # # Copyright (C) 2023 The Android Open Source Project # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. import argparse from datetime import datetime from threading import Thread import os import re import sys import time import traceback # May import this package in the workstation with: # pip install paramiko from paramiko import SSHClient from paramiko import AutoAddPolicy from prepare_tracing import adb_run # Usage: # ./calculate_time_offset.py --host_username root --host_ip 10.42.0.247 # --guest_serial 10.42.0.247 --clock_name CLOCK_REALTIME # or # ./calculate_time_offset.py --host_username root --host_ip 10.42.0.247 # --guest_serial 10.42.0.247 --clock_name CLOCK_REALTIME --mode trace class Device: # Get the machine time def __init__(self, clock_name, mode): if clock_name != None: self.time_cmd += f' {clock_name}' if mode == "trace": if clock_name == None: raise SystemExit("Error: with trace mode, clock_name must be specified") self.time_cmd = f'{self.time_cmd} --trace' def GetTime(self): pass def ParseTime(self, time_str): pattern = r'\d+' match = re.search(pattern, time_str) if match is None: raise Exception(f'Error: ParseTime no match time string: {time_str}') return int(match.group()) # Here is an example of time_util with --trace flag enable and given a clockname # will give a snapshot of the CPU counter and clock timestamp. # time_util CLOCK_REALTIME --trace # 6750504532818 CPU tick value # 1686355159395639260 CLOCK_REATIME # 0.0192 CPU tick per nanosecond # # The example's output is ts_str def TraceTime(self, ts_str): lines = ts_str.split("\n") if len(lines) < 3: raise Exception(f'Error: TraceTime input is wrong {ts_str}.' 'Expecting three lines of input: ' 'cpu_tick_value, CLOCK value, and CPU cycles per nanoseconds') self.cpu_ts = int(lines[0]) self.clock_ts = int(lines[1]) self.cpu_cycles = float(lines[2]) class QnxDevice(Device): def __init__(self, host_username, host_ip, clock_name, mode): self.sshclient = SSHClient() self.sshclient.load_system_host_keys() self.sshclient.set_missing_host_key_policy(AutoAddPolicy()) self.sshclient.connect(host_ip, username=host_username) self.time_cmd = "/bin/QnxClocktime" super().__init__(clock_name, mode) def GetTime(self): (stdin, stdout, stderr) = self.sshclient.exec_command(self.time_cmd) return stdout def ParseTime(self, time_str): time_decoded_str = time_str.read().decode() return super().ParseTime(time_decoded_str) def TraceTime(self): result_str = self.GetTime() ts_str = result_str.read().decode() super().TraceTime(ts_str) class AndroidDevice(Device): def __init__(self, guest_serial, clock_name, mode): adb_run(guest_serial, ['connect']) self.time_cmd = "/vendor/bin/android.automotive.time_util" self.serial = guest_serial super().__init__(clock_name, mode) def GetTime(self): ts = adb_run(self.serial, ['shell', self.time_cmd]) return ts def TraceTime(self): super().TraceTime(self.GetTime()) # measure the time offset between device1 and device2 with ptp, # return the average value over cnt times. def Ptp(device1, device2): # set up max delay as 100 milliseconds max_delay_ms = 100000000 # set up max offset as 2 milliseconds max_offset_ms = 2000000 max_retry = 20 for i in range(max_retry): time1_d1_str = device1.GetTime() time1_d2_str = device2.GetTime() time2_d2_str = device2.GetTime() time2_d1_str = device1.GetTime() time1_d1 = device1.ParseTime(time1_d1_str) time2_d1 = device1.ParseTime(time2_d1_str) time1_d2 = device2.ParseTime(time1_d2_str) time2_d2 = device2.ParseTime(time2_d2_str) offset = (time1_d2 + time2_d2 - time1_d1 - time2_d1)/2 if time2_d1 - time1_d1 > max_delay_ms or time2_d2 - time2_d2 > max_delay_ms or abs(offset) > max_offset_ms: print(f'Network delay is too big, ignore this measure {offset}') else: return int(offset) raise SystemExit(f"Network delay is still too big after {max_retry} retries") # It assumes device1 and device2 have access to the same CPU counter and uses the cpu counter # as the time source to calculate the time offset between device1 and device2. def TraceTimeOffset(device1, device2): offset = device2.clock_ts - device1.clock_ts - ((device2.cpu_ts - device1.cpu_ts)/device2.cpu_cycles) return int(offset) def CalculateTimeOffset(host_username, hostip, guest_serial, clock_name, mode): qnx = QnxDevice(host_username, hostip, clock_name, mode) android = AndroidDevice(guest_serial, clock_name, mode) if mode == "trace": return TraceTimeOffset(qnx, android) else: return Ptp(qnx, android) def ParseArguments(): parser = argparse.ArgumentParser() parser.add_argument('--host_ip', required=True, help = 'host IP address') parser.add_argument('--host_username', required=True, help = 'host username') parser.add_argument('--guest_serial', required=True, help = 'guest VM serial number') parser.add_argument('--clock_name', required=False, choices =['CLOCK_REALTIME','CLOCK_MONOTONIC'], help = 'clock that will be used for the measument. By default CPU counter is used.') parser.add_argument('--mode', choices=['ptp', 'trace'], default='ptp', help='select the mode of operation. If the two devices have access of the same CPU counter, ' 'use trace option. Otherwise use ptp option.') return parser.parse_args() def main(): args = ParseArguments() time_offset = CalculateTimeOffset(args.host_username, args.host_ip, args.guest_serial, args.clock_name, args.mode) print(f'Time offset between host and guest is {time_offset} nanoseconds') if __name__ == "__main__": main()