Wednesday, February 1, 2017

psutil 5.1.0: temperatures, batteries and cpu frequency

OK, here's another psutil release. Main highlights of this release are sensors-related APIs.


It is now possible to retrieve hardware temperatures. The relevant commit is here. Unfortunately this is Linux only. I couldn't manage to implement this on other platforms mainly for two reasons:

  • On Windows it is hard to do this in a hardware agnostic fashion. I bumped into 3 different approaches, all using WMI, and none of them worked with my hardware so I gave up. 
  • On OSX it appears it is possible to retrieve temperatures relatively easy, but I have a virtualized OSX box which does not support sensors, so basically I gave up on this due to lack of hardware. If somebody wants to give it a try be my guest.

>>> import psutil
>>> psutil.sensors_temperatures()
{'acpitz': [shwtemp(label='', current=47.0, high=103.0, critical=103.0)],
 'asus': [shwtemp(label='', current=47.0, high=None, critical=None)],
 'coretemp': [shwtemp(label='Physical id 0', current=52.0, high=100.0, critical=100.0),
              shwtemp(label='Core 0', current=45.0, high=100.0, critical=100.0),
              shwtemp(label='Core 1', current=52.0, high=100.0, critical=100.0),
              shwtemp(label='Core 2', current=45.0, high=100.0, critical=100.0),
              shwtemp(label='Core 3', current=47.0, high=100.0, critical=100.0)]}

Battery status

This works on Linux, Windows and FreeBSD and provides battery status information. The relevant commit is here.
>>> import psutil
>>> def secs2hours(secs):
...     mm, ss = divmod(secs, 60)
...     hh, mm = divmod(mm, 60)
...     return "%d:%02d:%02d" % (hh, mm, ss)
>>> battery = psutil.sensors_battery()
>>> battery
sbattery(percent=93, secsleft=16628, power_plugged=False)
>>> print("charge = %s%%, time left = %s" % (batt.percent, secs2hours(batt.secsleft)))
charge = 93%, time left = 4:37:08

CPU frequency

Available under Linux, Windows and OSX. Relevant commit is here. Linux is the only platform which reports the real-time value (always changing), on all other platforms current frequency is represented as the nominal “fixed” value.

>>> import psutil
>>> psutil.cpu_freq()
scpufreq(current=931.42925, min=800.0, max=3500.0)
>>> psutil.cpu_freq(percpu=True)
[scpufreq(current=2394.945, min=800.0, max=3500.0),
 scpufreq(current=2236.812, min=800.0, max=3500.0),
 scpufreq(current=1703.609, min=800.0, max=3500.0),
 scpufreq(current=1754.289, min=800.0, max=3500.0)]

What CPU a process is on

This will let you know what CPU number a process is currently running on, which is somewhat related to the existent cpu_affinity() functionality. The relevant commit is here. It is interesting to use this method to visualize how the OS scheduler continuously evenly reassigns processes to different CPUs  (see script).

CPU affinity

...can now be used as an alias for "set affinity against all eligible CPUs". This was implemented because it turns out on Linux it is not always possible to set affinity against all CPUs. Having such an alias is also a shortcut to avoid doing this, which is kinda verbose:

Other bug fixes

See full list.