My GSM carrier rounds all used data up to 100KB. Which means that if some app is sending/receiving 500 bytes, I get charged for 100KB.
Lately I observed that I go through several hundred megabytes per day.
Data usage in phone shows that I used ~ 400MB, while carrier charged me for over 2GB of data.
In detailed billing I see literally thousands of short connections (multiple per minute, 24 hours a day), each using 100KB - which means that actual data transfer is much lower.
Carrier helpdesk said that they can't tell me what I'm using the data for. Phone shows real data transfer, which in my case is useless.
What can I do to find out what application/process is sending lots of small packets of data (or receives)?
If it helps with anything, I'm using Motorola Moto G2 (only 1 SIM has data transfer enabled), and it's running Android 5.0.2.
While debugging the problem, I disabled Google Backup Services from using 3G (only works over Wifi now), and an hour ago I disabled it altogether. But given that it was disabled over 3G, I don't think it's the culprit.