Sony Xperia User Manual page 440

Tap application name at bottom to check data usage according to application.
Enabling Restriction on Mobile Data Traffic in Background
In data window,
If confirmation appears, follow onscreen instructions.
Enabling Showing of Wi-Fi usage
In data usage window,
If Show Wi-Fi
window. Tap "WI-FI" tab to make settings for restricting mobile data use with Wi-Fi.
Restricting Applications from Using Wi-Fi Network in the Background
In data usage window,
applications from using Wi-Fi network
Tap
Setting is available when Wi-Fi is connected.
Set Mobile Networks
In data usage screen,
11
Restrict background data/Allow background data
Show Wi-Fi/Hide Wi-Fi
is enabled, "MOBILE"/"WI-FI" tabs appear at the top of data usage
Network restrictions
of Wi-Fi network to clear restriction.
Mobile networks
of Wi-Fi network to restrict
Set each item