编写监控程序读取磁盘监控文件/proc/diskstats，找出磁盘读的次数、写的次数，读字节数、磁盘写耗时；

以下是 Python 编写的监控程序，可以读取 /proc/diskstats 文件，并输出磁盘读写次数、读字节数、磁盘写耗时等信息：

import time

def get_disk_stats():
    with open('/proc/diskstats', 'r') as f:
        data = f.readlines()

    disk_stats = {}

    for line in data:
        fields = line.strip().split()
        device_name = fields[2]
        reads_completed = int(fields[3])
        reads_merged = int(fields[4])
        sectors_read = int(fields[5])
        ms_spent_reading = int(fields[6])
        writes_completed = int(fields[7])
        writes_merged = int(fields[8])
        sectors_written = int(fields[9])
        ms_spent_writing = int(fields[10])
        io_in_progress = int(fields[11])
        ms_spent_io = int(fields[12])

        if device_name.startswith('sd'):
            disk_stats[device_name] = {
                'reads_completed': reads_completed,
                'reads_merged': reads_merged,
                'sectors_read': sectors_read,
                'ms_spent_reading': ms_spent_reading,
                'writes_completed': writes_completed,
                'writes_merged': writes_merged,
                'sectors_written': sectors_written,
                'ms_spent_writing': ms_spent_writing,
                'io_in_progress': io_in_progress,
                'ms_spent_io': ms_spent_io
            }

    return disk_stats

def print_disk_stats():
    disk_stats_start = get_disk_stats()
    time.sleep(1)
    disk_stats_end = get_disk_stats()

    for device_name, stats_start in disk_stats_start.items():
        stats_end = disk_stats_end[device_name]

        reads_completed = stats_end['reads_completed'] - stats_start['reads_completed']
        writes_completed = stats_end['writes_completed'] - stats_start['writes_completed']
        sectors_read = stats_end['sectors_read'] - stats_start['sectors_read']
        sectors_written = stats_end['sectors_written'] - stats_start['sectors_written']
        ms_spent_reading = stats_end['ms_spent_reading'] - stats_start['ms_spent_reading']
        ms_spent_writing = stats_end['ms_spent_writing'] - stats_start['ms_spent_writing']

        print(f'Device: {device_name}')
        print(f'Reads completed: {reads_completed}')
        print(f'Writes completed: {writes_completed}')
        print(f'Sectors read: {sectors_read}')
        print(f'Sectors written: {sectors_written}')
        print(f'Milliseconds spent reading: {ms_spent_reading}')
        print(f'Milliseconds spent writing: {ms_spent_writing}')
        print('------------------------------------------')

while True:
    print_disk_stats()

该程序会每秒钟输出一次磁盘读写相关的信息，直到程序被中断。