Re: [PATCH v2 01/21] libtracefs: Added new API tracefs_sql()

On Tue, Aug 3, 2021 at 6:23 AM Steven Rostedt [off-list ref] wrote:

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

This adds the API tracefs_sql() that takes a tep_handle handler, a name,
and a SQL string and parses it to produce a tracefs_synth synthetic event
handler.

Currently it only supports simple SQL of the type:

  SELECT start.common_pid AS pid, end.common_timestamp.usecs AS usecs
    FROM sched_waking AS start JOIN sched_switch AS end
    ON start.pid = end.next_pid

Special thanks to:

  Lukas Bulwahn for first introducing the idea at RT Summit on the Summit
    Spring of 2019.

Thanks, Steven, for putting this idea to life.

I hope that the tracing users appreciate this new declarative
interface using SQL and it makes tracing events easier comprehensible
to a larger community of users.

Lukas