Once you've launched or injected into a program, you can stop and start data collection whilst the program is running.
This is a high level switch that controls all data collection, regardless of any other settings.
With data collection off, the target program runs at close to normal speed.
Temporarily turning off collection can be a good idea if you need to take actions to get the program into the right state for validation.
You can also turn data off from the start and only turn it on when you need it.
or click on the green icon on the session toolbar to start collecting.
or click on the red icon on the session toolbar to stop.
If the instrumentation detail setting is set to use breakpoints, the collect data from application setting is disabled - data collection is always on - you can't turn it off.
When the ability to change this setting is disabled both of the above icons will be greyed out, and so will any "collect data from application" checkboxes on launch dialogs etc.