This program gathers statistics about suspending and writes them to /var/log/suspend. It is solely intended for usage on laptops or other devices that can enter a sleep state and operate on a battery.
Examples of the data collected include:
- start and end time of the suspend period
- time spent in suspend
- battery consumption during suspend, in both joules and percents
- S0ix residency (how much time was spent in any S0 state).
The best way to use this program is by running it as a suspend hook before and after suspending. Depending on the program you use to suspend, this should be done as follows:
zzz: Create a symlink calledmeasure_startin/etc/zzz.d/suspendand one calledmeasure_endin/etc/zzz.d/resume. See https://man.voidlinux.org/zzz.8#FILES.elogind: Create the symlinks mentioned above in/usr/local/bin, and then create a script that calls eithermeasure_startormeasure_end, depending on the arguments passed to it. See https://wiki.gentoo.org/wiki/Elogind#Suspend.2FHibernate_Resume.2FThaw_hook_scripts.
Entries in /var/log/suspend look roughly like this (not all options are enabled):
05-04-2025 18:41:21 05-04-2025 21:21:05 02:39:44 -2.2% -0.236W 99.9%
From left to right: start time, end time, time spent in suspend, battery percentage consumed, average power draw during suspend, S0ix residency percentage.