Re: [PATCH v2 28/40] tracing: Add support for 'field variables'

[Steven Rostedt]

On Tue,  5 Sep 2017 16:57:40 -0500
Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx> wrote:

> Users should be able to directly specify event fields in hist trigger
> 'actions' rather than being forced to explicitly create a variable for
> that purpose.
> 
> Add support allowing fields to be used directly in actions, which
> essentially does just that - creates 'invisible' variables for each
> bare field specified in an action.  If a bare field refers to a field
> on another (matching) event, it even creates a special histogram for
> the purpose (since variables can't be defined on an existing histogram
> after histogram creation).

Can you show some examples here to describe what you mean better?

-- Steve

> 
> Signed-off-by: Tom Zanussi <tom.zanussi@xxxxxxxxxxxxxxx>
> ---
>  kernel/trace/trace_events_hist.c | 452 ++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 451 insertions(+), 1 deletion(-)
> 
>