1 files changed, 51 insertions, 0 deletions
diff --git a/synapse/metrics/__init__.py b/synapse/metrics/__init__.py
index 9233ea3da9..d7bcad8a8a 100644
--- a/synapse/metrics/__init__.py
+++ b/synapse/metrics/__init__.py
@@ -18,8 +18,12 @@ from __future__ import absolute_import
 
 import logging
 from resource import getrusage, getpagesize, RUSAGE_SELF
+import functools
 import os
 import stat
+import time
+
+from twisted.internet import reactor
 
 from .metric import (
     CounterMetric, CallbackMetric, DistributionMetric, CacheMetric
@@ -144,3 +148,50 @@ def _process_fds():
     return counts
 
 get_metrics_for("process").register_callback("fds", _process_fds, labels=["type"])
+
+reactor_metrics = get_metrics_for("reactor")
+tick_time = reactor_metrics.register_distribution("tick_time")
+pending_calls_metric = reactor_metrics.register_distribution("pending_calls")
+
+
+def runUntilCurrentTimer(func):
+
+    @functools.wraps(func)
+    def f(*args, **kwargs):
+        now = reactor.seconds()
+        num_pending = 0
+
+        # _newTimedCalls is one long list of *all* pending calls. Below loop
+        # is based off of impl of reactor.runUntilCurrent
+        for delayed_call in reactor._newTimedCalls:
+            if delayed_call.time > now:
+                break
+
+            if delayed_call.delayed_time > 0:
+                continue
+
+            num_pending += 1
+
+        num_pending += len(reactor.threadCallQueue)
+
+        start = time.time() * 1000
+        ret = func(*args, **kwargs)
+        end = time.time() * 1000
+        tick_time.inc_by(end - start)
+        pending_calls_metric.inc_by(num_pending)
+        return ret
+
+    return f
+
+
+try:
+    # Ensure the reactor has all the attributes we expect
+    reactor.runUntilCurrent
+    reactor._newTimedCalls
+    reactor.threadCallQueue
+
+    # runUntilCurrent is called when we have pending calls. It is called once
+    # per iteratation after fd polling.
+    reactor.runUntilCurrent = runUntilCurrentTimer(reactor.runUntilCurrent)
+except AttributeError:
+    pass