perf scripts python: export-to-sqlite.py: Export switch events

Export switch events to a new table 'context_switches' and create a view
'context_switches_view'. The table and view will show automatically in
the exported-sql-viewer.py script.

If the table ends up empty, then it and the view are dropped.

Committer testing:

Use the exported-sql-viewer.py and look at "Tables" ->
"context_switches":

  id  machine_id  time             cpu  thread_out_id  comm_out_id  thread_in_id  comm_in_id  flags
  1   1           187836111885918  7    1              1            2             2           3
  2   1           187836111889369  7    1              1            2             2           0
  3   1           187836112464618  7    2              3            1             1           1
  4   1           187836112465511  7    2              3            1             1           0

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Link: http://lkml.kernel.org/r/20190710085810.1650-21-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/scripts/python/export-to-sqlite.py

@@ -306,6 +306,17 @@ def do_query_(q):
 		'last_cstate	integer,'
 		'wake_reason	integer)')
 
+do_query(query, 'CREATE TABLE context_switches ('
+		'id		integer		NOT NULL	PRIMARY KEY,'
+		'machine_id	bigint,'
+		'time		bigint,'
+		'cpu		integer,'
+		'thread_out_id	bigint,'
+		'comm_out_id	bigint,'
+		'thread_in_id	bigint,'
+		'comm_in_id	bigint,'
+		'flags		integer)')
+
 # printf was added to sqlite in version 3.8.3
 sqlite_has_printf = False
 try:
@@ -530,6 +541,29 @@ def emit_to_hex(x):
 	' INNER JOIN selected_events ON selected_events.id = evsel_id'
 	' WHERE selected_events.name IN (\'cbr\',\'mwait\',\'exstop\',\'pwre\',\'pwrx\')')
 
+do_query(query, 'CREATE VIEW context_switches_view AS '
+	'SELECT '
+		'context_switches.id,'
+		'context_switches.machine_id,'
+		'context_switches.time,'
+		'context_switches.cpu,'
+		'th_out.pid AS pid_out,'
+		'th_out.tid AS tid_out,'
+		'comm_out.comm AS comm_out,'
+		'th_in.pid AS pid_in,'
+		'th_in.tid AS tid_in,'
+		'comm_in.comm AS comm_in,'
+		'CASE	  WHEN context_switches.flags = 0 THEN \'in\''
+			' WHEN context_switches.flags = 1 THEN \'out\''
+			' WHEN context_switches.flags = 3 THEN \'out preempt\''
+			' ELSE context_switches.flags '
+		'END AS flags'
+	' FROM context_switches'
+	' INNER JOIN threads AS th_out ON th_out.id   = context_switches.thread_out_id'
+	' INNER JOIN threads AS th_in  ON th_in.id    = context_switches.thread_in_id'
+	' INNER JOIN comms AS comm_out ON comm_out.id = context_switches.comm_out_id'
+	' INNER JOIN comms AS comm_in  ON comm_in.id  = context_switches.comm_in_id')
+
 do_query(query, 'END TRANSACTION')
 
 evsel_query = QSqlQuery(db)
@@ -571,6 +605,8 @@ def emit_to_hex(x):
 exstop_query.prepare("INSERT INTO exstop VALUES (?, ?)")
 pwrx_query = QSqlQuery(db)
 pwrx_query.prepare("INSERT INTO pwrx VALUES (?, ?, ?, ?)")
+context_switch_query = QSqlQuery(db)
+context_switch_query.prepare("INSERT INTO context_switches VALUES (?, ?, ?, ?, ?, ?, ?, ?, ?)")
 
 def trace_begin():
 	printdate("Writing records...")
@@ -620,6 +656,8 @@ def trace_end():
 		drop("pwrx")
 		if is_table_empty("cbr"):
 			drop("cbr")
+	if is_table_empty("context_switches"):
+		drop("context_switches")
 
 	if (unhandled_count):
 		printdate("Warning: ", unhandled_count, " unhandled events")
@@ -753,3 +791,6 @@ def synth_data(id, config, raw_buf, *x):
 		pwrx(id, raw_buf)
 	elif config == 5:
 		cbr(id, raw_buf)
+
+def context_switch_table(*x):
+	bind_exec(context_switch_query, 9, x)