获得树莓派运行时的信息

2019-10-20

使用Python获得树莓派运行时的信息

一、获取CPU的信息

1. vcgencmd命令

树莓派提供了vcgencmd命令,可以用来查看树莓派的硬件情况。
使用以下命令来查看vcgencmd可用的参数列表

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pi@raspberrypi:~ $ vcgencmd commands
commands="vcos, ap_output_control, ap_output_post_processing, vchi_test_init, vchi_test_exit, vctest_memmap, vctest_start, vctest_stop, vctest_set, vctest_get, pm_set_policy, pm_get_status, pm_show_stats, pm_start_logging, pm_stop_logging, version, commands, set_vll_dir, set_backlight, set_logging, get_lcd_info, arbiter, cache_flush, otp_dump, test_result, codec_enabled, get_camera, get_mem, measure_clock, measure_volts, scaling_kernel, scaling_sharpness, get_hvs_asserts, get_throttled, measure_temp, get_config, hdmi_ntsc_freqs, hdmi_adjust_clock, hdmi_status_show, hvs_update_fields, pwm_speedup, force_audio, hdmi_stream_channels, hdmi_channel_map, display_power, read_ring_osc, memtest, dispmanx_list, get_rsts, schmoo, render_bar, disk_notify, inuse_notify, sus_suspend, sus_status, sus_is_enabled, sus_stop_test_thread, egl_platform_switch, mem_validate, mem_oom, mem_reloc_stats, hdmi_cvt, hdmi_timings, file"

其中

1 2	pi@raspberrypi:~ $ vcgencmd measure_temp temp=34.3'C

可以用来查看当前CPU的温度

2. top命令

top命令可以实时动态地查看系统的整体运行情况。

1	pi@raspberrypi:~ $ top -n<次数>: 循环显示的次数

pi@raspberrypi:~ $ top -n1
top - 23:35:53 up 1 min,  1 user,  load average: 0.22, 0.13, 0.05
Tasks: 114 total,   1 running,  53 sleeping,   0 stopped,   0 zombie
%Cpu(s):  2.2 us,  2.1 sy,  0.0 ni, 94.8 id,  0.9 wa,  0.0 hi,  0.1 si,  0.0 st
KiB Mem :   765604 total,   635916 free,    36532 used,    93156 buff/cache
KiB Swap:   102396 total,   102396 free,        0 used.   674900 avail Mem

其中第三行 2.2 us 表示用户占用CPU的百分比为2.2%

3. 代码实现

import os

def getCPUinfo():
    # temperature of CPU
    with os.popen('vcgencmd measure_temp') as p:
        temperature = p.readline().replace("temp=","").replace("'C\n","")
    
    # percent of CPU load
    with os.popen("top -n1 | awk '/Cpu\(s\):/ {print $2}'") as p:
        load = p.readline().strip()

    return (temperature,load)

二、获取内存的信息

1. free命令

显示内存的使用情况

1	pi@raspberrypi:~ $ free (选项)

pi@raspberrypi:~ $ free -m #以MB为单位显示内存使用情况
              total        used        free      shared  buff/cache   available
Mem:            747          36         602          14         108         648
Swap:            99           0          99

2. 代码实现

def getRAMinfo():
    """
    Return the list of RAM information (unit=MB)
    Index 0: total
    Index 1: used
    Index 2: free
    """
    with os.popen("free -m") as p:
        line = p.readlines()[1]
        ram_info = line.split()[1:4]
    return ram_info

三、获取硬盘的信息

1. df命令

显示磁盘的相关信息

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pi@raspberrypi:~ $ df (选项) (参数)
# -h: 以可读性较高的方式来显示信息
# / : 显示 / 目录中可用空间量

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pi@raspberrypi:~ $ df -h /
Filesystem      Size  Used Avail Use% Mounted on
/dev/root        15G  2.5G   12G  18% /

2. 代码实现

def getDiskinfo():
    """
    Return the list of disk space information
    Index 0: total disk space
    Index 1: used disk space
    Index 2: remaining disk space
    Index 3: percentage of disk used
    """
    with os.popen("df -h /") as p:
        line = p.readlines()[1]
        disk_info = line.split()[1:5]
    return disk_info