test/trace_processor/network/kfree_skb_test.sql

SELECT
  ts,
  value,
  EXTRACT_ARG(arg_set_id, 'protocol') AS prot
FROM
  counter AS c
LEFT JOIN
  counter_track AS t
  ON c.track_id = t.id
WHERE
  name GLOB "Kfree Skb IP Prot"
ORDER BY ts;