I'm trying to learn how to set up Panels caching. I watched a video on mastering Drupal caching and I have the book by Earl Miles on Panels and Views, Drupal's Building Blocks, but unfortunately there's not a chapter specifically on caching.
So, I have a panel that overrides the user profile, and on this panel I have a variant that has a number of views content panes. I would like to cache these content panes per user profile displayed, since obviously they should be different for each user who is viewed.
Each of these content panes has a Contextual filter on Content: Author UID.
The value is supplied to Panels by the Argument input option in Views, for which the Content: Author uid source is set to From context and Required context is set to User ID:
In Panels, on the Simple cache configuration screen, for the Granularity, I can choose Argument or Context, and the help text is this:
If "arguments" are selected, this content will be cached per individual argument to the entire display; if "contexts" are selected, this content will be cached per unique context in the pane or display; if "neither" there will be only one cache for this pane.
But in Views, the option is called argument input and the value I chose was from context. So am I dealing with an argument or a context?
If possible, both a general answer describing the difference between argument and context in this case and a specific answer to my question would be fantastic.