Time how long we're spending on the database thread

synapse/app/homeserver.py

@@ -274,6 +274,8 @@ def setup():
 
     hs.get_pusherpool().start()
 
+    hs.get_datastore().start_profiling()
+
     if config.daemonize:
         print config.pid_file
         daemon = Daemonize(

synapse/storage/_base.py

@@ -85,6 +85,28 @@ class SQLBaseStore(object):
         self._db_pool = hs.get_db_pool()
         self._clock = hs.get_clock()
 
+        self._previous_txn_total_time = 0
+        self._current_txn_total_time = 0
+        self._previous_loop_ts = 0
+
+    def start_profiling(self):
+        self._previous_loop_ts = self._clock.time_msec()
+
+        def loop():
+            curr = self._current_txn_total_time
+            prev = self._previous_txn_total_time
+            self._previous_txn_total_time = curr
+
+            time_now = self._clock.time_msec()
+            time_then = self._previous_loop_ts
+            self._previous_loop_ts = time_now
+
+            ratio = (curr - prev)/(time_now - time_then)
+
+            logger.info("Total database time: %.3f", ratio)
+
+        self._clock.looping_call(loop, 1000)
+
     @defer.inlineCallbacks
     def runInteraction(self, desc, func, *args, **kwargs):
         """Wraps the .runInteraction() method on the underlying db_pool."""
@@ -114,6 +136,9 @@ class SQLBaseStore(object):
                         "[TXN END] {%s} %f",
                         name, end - start
                     )
+
+                    self._current_txn_total_time += end - start
+
         with PreserveLoggingContext():
             result = yield self._db_pool.runInteraction(
                 inner_func, *args, **kwargs