diff --git a/changelog.d/6446.misc b/changelog.d/6446.misc
new file mode 100644
index 000000000..c42df16f1
--- /dev/null
+++ b/changelog.d/6446.misc
@@ -0,0 +1 @@
+Add benchmarks for LruCache.
diff --git a/synmark/__main__.py b/synmark/__main__.py
index ac59befbd..17df9ddeb 100644
--- a/synmark/__main__.py
+++ b/synmark/__main__.py
@@ -14,6 +14,7 @@
 # limitations under the License.
 
 import sys
+from argparse import REMAINDER
 from contextlib import redirect_stderr
 from io import StringIO
 
@@ -21,7 +22,7 @@ import pyperf
 from synmark import make_reactor
 from synmark.suites import SUITES
 
-from twisted.internet.defer import ensureDeferred
+from twisted.internet.defer import Deferred, ensureDeferred
 from twisted.logger import globalLogBeginner, textFileLogObserver
 from twisted.python.failure import Failure
 
@@ -40,7 +41,8 @@ def make_test(main):
         file_out = StringIO()
         with redirect_stderr(file_out):
 
-            d = ensureDeferred(main(reactor, loops))
+            d = Deferred()
+            d.addCallback(lambda _: ensureDeferred(main(reactor, loops)))
 
             def on_done(_):
                 if isinstance(_, Failure):
@@ -50,6 +52,7 @@ def make_test(main):
                 return _
 
             d.addBoth(on_done)
+            reactor.callWhenRunning(lambda: d.callback(True))
             reactor.run()
 
         return d.result
@@ -62,11 +65,13 @@ if __name__ == "__main__":
     def add_cmdline_args(cmd, args):
         if args.log:
             cmd.extend(["--log"])
+        cmd.extend(args.tests)
 
     runner = pyperf.Runner(
-        processes=3, min_time=2, show_name=True, add_cmdline_args=add_cmdline_args
+        processes=3, min_time=1.5, show_name=True, add_cmdline_args=add_cmdline_args
     )
     runner.argparser.add_argument("--log", action="store_true")
+    runner.argparser.add_argument("tests", nargs=REMAINDER)
     runner.parse_args()
 
     orig_loops = runner.args.loops
@@ -79,6 +84,11 @@ if __name__ == "__main__":
             )
         setupdb()
 
+    if runner.args.tests:
+        SUITES = list(
+            filter(lambda x: x[0].__name__.split(".")[-1] in runner.args.tests, SUITES)
+        )
+
     for suite, loops in SUITES:
         if loops:
             runner.args.loops = loops
diff --git a/synmark/suites/__init__.py b/synmark/suites/__init__.py
index cfa3b0ba3..d8445fc3d 100644
--- a/synmark/suites/__init__.py
+++ b/synmark/suites/__init__.py
@@ -1,3 +1,9 @@
-from . import logging
+from . import logging, lrucache, lrucache_evict
 
-SUITES = [(logging, 1000), (logging, 10000), (logging, None)]
+SUITES = [
+    (logging, 1000),
+    (logging, 10000),
+    (logging, None),
+    (lrucache, None),
+    (lrucache_evict, None),
+]
diff --git a/synmark/suites/lrucache.py b/synmark/suites/lrucache.py
new file mode 100644
index 000000000..69ab042cc
--- /dev/null
+++ b/synmark/suites/lrucache.py
@@ -0,0 +1,34 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from pyperf import perf_counter
+
+from synapse.util.caches.lrucache import LruCache
+
+
+async def main(reactor, loops):
+    """
+    Benchmark `loops` number of insertions into LruCache without eviction.
+    """
+    cache = LruCache(loops)
+
+    start = perf_counter()
+
+    for i in range(loops):
+        cache[i] = True
+
+    end = perf_counter() - start
+
+    return end
diff --git a/synmark/suites/lrucache_evict.py b/synmark/suites/lrucache_evict.py
new file mode 100644
index 000000000..532b1cc70
--- /dev/null
+++ b/synmark/suites/lrucache_evict.py
@@ -0,0 +1,35 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from pyperf import perf_counter
+
+from synapse.util.caches.lrucache import LruCache
+
+
+async def main(reactor, loops):
+    """
+    Benchmark `loops` number of insertions into LruCache where half of them are
+    evicted.
+    """
+    cache = LruCache(loops // 2)
+
+    start = perf_counter()
+
+    for i in range(loops):
+        cache[i] = True
+
+    end = perf_counter() - start
+
+    return end