In the timeline diagrams you will see two curves for the specified branch and
target: one for "-Os", and another for "-O2" results.
Data view options are the following:
Code size represents summarized object sizes.
Compilation time shows the summarized object compilation times.
Execution time shows the execution time of executable projects.
All results - objects shows all results related to object measurements (code size and compilation time).
Raw numbers - objects shows all results related to object measurements in numbers (code size and compilation time) using raw numbers.
Use Normalized to see multiple curves in one diagram.
If you are interested in how we measure there is more info
For more info about this query type see some examples here.