We can use the psutil (Python system and process utilities) module in Python scripts to retrieve information about our system configuration, running processes, and system utilization on the device.

psutil is useful mainly for system monitoring, profiling, limiting process resources, and the management of running processes. In particular,it can be used to develop new profilers and monitoring tools.

psutil implements many functionalities offered by UNIX command-line tools such as: ps, top, lsof, netstat, ifconfig, who, df, kill, free, nice, ionice, iostat, iotop, uptime, pidof, tty, taskset, pmap.

psutil currently supports Linux, Mac, and Windows systems. However, some functionalities, such as access to temperature sensor data, are limited to Linux systems. Also psutil on new architectures might provide incomplete information.

psutil provides resource information about CPU, memory, disks, processes, sensors, see this link.

Below, we report some methods that can be used to retrieve information about your system (retrieved from this link)

CPU

>>> import psutil
>>>
>>> psutil.cpu_times()
scputimes(user=3961.46, nice=169.729, system=2150.659, idle=16900.540, iowait=629.59, irq=0.0, softirq=19.42, steal=0.0, guest=0, nice=0.0)
>>>
>>> for x in range(3):
...     psutil.cpu_percent(interval=1)
...
4.0
5.9
3.8
>>>
>>> for x in range(3):
...     psutil.cpu_percent(interval=1, percpu=True)
...
[4.0, 6.9, 3.7, 9.2]
[7.0, 8.5, 2.4, 2.1]
[1.2, 9.0, 9.9, 7.2]
>>>
>>> for x in range(3):
...     psutil.cpu_times_percent(interval=1, percpu=False)
...
scputimes(user=1.5, nice=0.0, system=0.5, idle=96.5, iowait=1.5, irq=0.0, softirq=0.0, steal=0.0, guest=0.0, guest_nice=0.0)
scputimes(user=1.0, nice=0.0, system=0.0, idle=99.0, iowait=0.0, irq=0.0, softirq=0.0, steal=0.0, guest=0.0, guest_nice=0.0)
scputimes(user=2.0, nice=0.0, system=0.0, idle=98.0, iowait=0.0, irq=0.0, softirq=0.0, steal=0.0, guest=0.0, guest_nice=0.0)
>>>
>>> psutil.cpu_count()
4
>>> psutil.cpu_count(logical=False)
2
>>>
>>> psutil.cpu_stats()
scpustats(ctx_switches=20455687, interrupts=6598984, soft_interrupts=2134212, syscalls=0)
>>>
>>> psutil.cpu_freq()
scpufreq(current=931.42925, min=800.0, max=3500.0)
>>>
>>> psutil.getloadavg()  # also on Windows (emulated)
(3.14, 3.89, 4.67)

Memory

>>> psutil.virtual_memory()
svmem(total=10367352832, available=6472179712, percent=37.6, used=8186245120, free=2181107712, active=4748992512, inactive=2758115328, buffers=790724608, cached=3500347392, shared=787554304)
>>> psutil.swap_memory()
sswap(total=2097147904, used=296128512, free=1801019392, percent=14.1, sin=304193536, sout=677842944)
>>>

Disk

>>> psutil.disk_partitions()
[sdiskpart(device='/dev/sda1', mountpoint='/', fstype='ext4', opts='rw,nosuid', maxfile=255, maxpath=4096),
 sdiskpart(device='/dev/sda2', mountpoint='/home', fstype='ext, opts='rw', maxfile=255, maxpath=4096)]
>>>
>>> psutil.disk_usage('/')
sdiskusage(total=21378641920, used=4809781248, free=15482871808, percent=22.5)
>>>
>>> psutil.disk_io_counters(perdisk=False)
sdiskio(read_count=719566, write_count=1082197, read_bytes=18626220032, write_bytes=24081764352, read_time=5023392, write_time=63199568, read_merged_count=619166, write_merged_count=812396, busy_time=4523412)
>>>

Processes

>>> import psutil
>>> psutil.pids()
[1, 2, 3, 4, 5, 6, 7, 46, 48, 50, 51, 178, 182, 222, 223, 224, 268, 1215,
 1216, 1220, 1221, 1243, 1244, 1301, 1601, 2237, 2355, 2637, 2774, 3932,
 4176, 4177, 4185, 4187, 4189, 4225, 4243, 4245, 4263, 4282, 4306, 4311,
 4312, 4313, 4314, 4337, 4339, 4357, 4358, 4363, 4383, 4395, 4408, 4433,
 4443, 4445, 4446, 5167, 5234, 5235, 5252, 5318, 5424, 5644, 6987, 7054,
 7055, 7071]
>>>
>>> p = psutil.Process(7055)
>>> p
psutil.Process(pid=7055, name='python3', status='running', started='09:04:44')
>>> p.name()
'python3'
>>> p.exe()
'/usr/bin/python3'
>>> p.cwd()
'/home/giampaolo'
>>> p.cmdline()
['/usr/bin/python', 'main.py']
>>>
>>> p.pid
7055
>>> p.ppid()
7054
>>> p.children(recursive=True)
[psutil.Process(pid=29835, name='python3', status='sleeping', started='11:45:38'),
 psutil.Process(pid=29836, name='python3', status='waking', started='11:43:39')]
>>>
>>> p.parent()
psutil.Process(pid=4699, name='bash', status='sleeping', started='09:06:44')
>>> p.parents()
[psutil.Process(pid=4699, name='bash', started='09:06:44'),
 psutil.Process(pid=4689, name='gnome-terminal-server', status='sleeping', started='0:06:44'),
 psutil.Process(pid=1, name='systemd', status='sleeping', started='05:56:55')]
>>>
>>> p.status()
'running'
>>> p.username()
'giampaolo'
>>> p.create_time()
1267551141.5019531
>>> p.terminal()
'/dev/pts/0'
>>>
>>> p.uids()
puids(real=1000, effective=1000, saved=1000)
>>> p.gids()
pgids(real=1000, effective=1000, saved=1000)
>>>
>>> p.cpu_times()
pcputimes(user=1.02, system=0.31, children_user=0.32, children_system=0.1, iowait=0.0)
>>> p.cpu_percent(interval=1.0)
12.1
>>> p.cpu_affinity()
[0, 1, 2, 3]
>>> p.cpu_affinity([0, 1])  # set
>>> p.cpu_num()
1
>>>
>>> p.memory_info()
pmem(rss=10915840, vms=67608576, shared=3313664, text=2310144, lib=0, data=7262208, dirty=0)
>>> p.memory_full_info()  # "real" USS memory usage (Linux, macOS, Win only)
pfullmem(rss=10199040, vms=52133888, shared=3887104, text=2867200, lib=0, data=5967872, dirty=0, uss=6545408, pss=6872064, swap=0)
>>> p.memory_percent()
0.7823
>>> p.memory_maps()
[pmmap_grouped(path='/lib/x8664-linux-gnu/libutil-2.15.so', rss=32768, size=2125824, pss=32768, shared_clean=0, shared_dirty=0, private_clean=20480, private_dirty=12288, referenced=32768, anonymous=12288, swap=0),
 pmmap_grouped(path='/lib/x8664-linux-gnu/libc-2.15.so', rss=3821568, size=3842048, pss=3821568, shared_clean=0, shared_dirty=0, private_clean=0, private_dirty=3821568, referenced=3575808, anonymous=3821568, swap=0),
 pmmap_grouped(path='[heap]',  rss=32768, size=139264, pss=32768, shared_clean=0, shared_dirty=0, private_clean=0, private_dirty=32768, referenced=32768, anonymous=32768, swap=0),
 pmmap_grouped(path='[stack]', rss=2465792, size=2494464, pss=2465792, shared_clean=0, shared_dirty=0, private_clean=0, private_dirty=2465792, referenced=2277376, anonymous=2465792, swap=0),
 ...]
>>>
>>> p.io_counters()
pio(read_count=478001, write_count=59371, read_bytes=700416, write_bytes=69632, read_chars=456232, write_chars=517543)
>>>
>>> p.open_files()
[popenfile(path='/home/giampaolo/monit.py', fd=3, position=0, mode='r', flags=32768),
 popenfile(path='/var/log/monit.log', fd=4, position=235542, mode='a', flags=33793)]
>>>
>>> p.connections(kind='tcp')
[pconn(fd=115, family=<AddressFamily.AF_INET: 2>, type=<SocketType.SOCK_STREAM: 1>, laddr=addr(ip='10.0.0.1', port=48776), raddr=addr(ip='93.186.135.91', port=80), status='ESTABLISHED'),
 pconn(fd=117, family=<AddressFamily.AF_INET: 2>, type=<SocketType.SOCK_STREAM: 1>, laddr=addr(ip='10.0.0.1', port=43761), raddr=addr(ip='72.14.234.100', port=80), status='CLOSING')]
>>>
>>> p.num_threads()
4
>>> p.num_fds()
8
>>> p.threads()
[pthread(id=5234, user_time=22.5, system_time=9.2891),
 pthread(id=5237, user_time=0.0707, system_time=1.1)]
>>>
>>> p.num_ctx_switches()
pctxsw(voluntary=78, involuntary=19)
>>>
>>> p.nice()
0
>>> p.nice(10)  # set
>>>
>>> p.ionice(psutil.IOPRIO_CLASS_IDLE)  # IO priority (Win and Linux only)
>>> p.ionice()
pionice(ioclass=<IOPriority.IOPRIO_CLASS_IDLE: 3>, value=0)
>>>
>>> p.rlimit(psutil.RLIMIT_NOFILE, (5, 5))  # set resource limits (Linux only)
>>> p.rlimit(psutil.RLIMIT_NOFILE)
(5, 5)
>>>
>>> p.environ()
{'LC_PAPER': 'it_IT.UTF-8', 'SHELL': '/bin/bash', 'GREP_OPTIONS': '--color=auto',
'XDG_CONFIG_DIRS': '/etc/xdg/xdg-ubuntu:/usr/share/upstart/xdg:/etc/xdg',
 ...}
>>>
>>> p.as_dict()
{'status': 'running', 'num_ctx_switches': pctxsw(voluntary=63, involuntary=1), 'pid': 5457, ...}
>>> p.is_running()
True
>>> p.suspend()
>>> p.resume()
>>>
>>> p.terminate()
>>> p.kill()
>>> p.wait(timeout=3)
<Exitcode.EX_OK: 0>
>>>
>>> psutil.test()
USER         PID %CPU %MEM     VSZ     RSS TTY        START    TIME  COMMAND
root           1  0.0  0.0   24584    2240            Jun17   00:00  init
root           2  0.0  0.0       0       0            Jun17   00:00  kthreadd
...
giampaolo  31475  0.0  0.0   20760    3024 /dev/pts/0 Jun19   00:00  python2.4
giampaolo  31721  0.0  2.2  773060  181896            00:04   10:30  chrome
root       31763  0.0  0.0       0       0            00:05   00:00  kworker/0:1
>>>