Huawei Mate 8 - Manual (Page 173)

Power management
166
Touch Exit to disable the Ultra power plan.
Closing background apps when the screen is
locked
You can save a lot of power by closing background apps whenever the screen is locked.
1
Open Phone Manager.
2
Touch > Protected apps.
3
Turn off switches for non-essential apps to prevent them from running while the
screen is locked.
If you want an app to continue running after the screen is locked (such as a backup
app that is performing a backup), turn on the switch for that app.
Press the power button to lock the screen. Your phone will close all background apps
except those that are protected.
Preventing background apps from accessing
the Internet
Use the networked apps manager to prevent certain apps from connecting to the Internet
and using your data allowance.
1
Open Phone Manager.
2
Touch Traffic manager > Networked apps.
Enable selected power saving mode
Choose a suitable power saving mode