From f8bf83b811cf54b4ce668bcda6043d14c4980f00 Mon Sep 17 00:00:00 2001 From: Sean Date: Wed, 1 Sep 2021 11:55:31 +0100 Subject: [PATCH] Skip the final GC on shutdown to improve restart times (#10712) Use `gc.freeze()` on exit to exclude all existing objects from the final GC. In testing, this sped up shutdown by up to a few seconds. `gc.freeze()` runs in constant time, so there is little chance of performance regression. Signed-off-by: Sean Quah --- changelog.d/10712.feature | 1 + synapse/app/_base.py | 7 +++++++ 2 files changed, 8 insertions(+) create mode 100644 changelog.d/10712.feature diff --git a/changelog.d/10712.feature b/changelog.d/10712.feature new file mode 100644 index 000000000000..d04db6f26feb --- /dev/null +++ b/changelog.d/10712.feature @@ -0,0 +1 @@ +Skip final GC at shutdown to improve restart performance. diff --git a/synapse/app/_base.py b/synapse/app/_base.py index 39e28aff9fb6..6fc14930d1cd 100644 --- a/synapse/app/_base.py +++ b/synapse/app/_base.py @@ -12,6 +12,7 @@ # 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. +import atexit import gc import logging import os @@ -403,6 +404,12 @@ def run_sighup(*args, **kwargs): gc.collect() gc.freeze() + # Speed up shutdowns by freezing all allocated objects. This moves everything + # into the permanent generation and excludes them from the final GC. + # Unfortunately only works on Python 3.7 + if platform.python_implementation() == "CPython" and sys.version_info >= (3, 7): + atexit.register(gc.freeze) + def setup_sentry(hs): """Enable sentry integration, if enabled in configuration