This page acts as a reference guide for queries which often appear when performing ad-hoc analysis.
If collecting traces which including scheduling information (i.e. from ftrace) as well as userspace slices (i.e. from atrace), the actual time spent running on a CPU for each userspace slice can be computed: this is commonly known as the "CPU time" for a slice.
Firstly, setup the views to simplify subsequent queries:
DROP VIEW IF EXISTS slice_with_utid; CREATE VIEW slice_with_utid AS SELECT ts, dur, slice.name as slice_name, slice.id as slice_id, utid, thread.name as thread_name FROM slice JOIN thread_track ON thread_track.id = slice.track_id JOIN thread USING (utid); DROP TABLE IF EXISTS slice_thread_state_breakdown; CREATE VIRTUAL TABLE slice_thread_state_breakdown USING SPAN_LEFT_JOIN( slice_with_utid PARTITIONED utid, thread_state PARTITIONED utid );
Then, to compute the CPU time for all slices in the trace:
SELECT slice_id, slice_name, SUM(dur) AS cpu_time FROM slice_thread_state_breakdown WHERE state = 'Running' GROUP BY slice_id;
You can also compute CPU time for a specific slice:
SELECT slice_name, SUM(dur) AS cpu_time FROM slice_thread_state_breakdown WHERE slice_id = <your slice id> AND state = 'Running';
These queries can be varied easily to compute other similar metrics. For example to get the time spent "runnable" and in "uninterruptible sleep":
SELECT slice_id, slice_name, SUM(CASE state = 'R' THEN dur ELSE 0 END) AS runnable_time, SUM(CASE state = 'D' THEN dur ELSE 0 END) AS uninterruptible_time FROM slice_thread_state_breakdown GROUP BY slice_id;