1 files changed, 23 insertions, 0 deletions
diff --git a/synapse/config/server.py b/synapse/config/server.py
index 28b4e5f50c..89d61a0503 100644
--- a/synapse/config/server.py
+++ b/synapse/config/server.py
@@ -1,5 +1,6 @@
# -*- coding: utf-8 -*-
# Copyright 2014-2016 OpenMarket Ltd
+# Copyright 2017 New Vector Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
@@ -29,6 +30,7 @@ class ServerConfig(Config):
self.user_agent_suffix = config.get("user_agent_suffix")
self.use_frozen_dicts = config.get("use_frozen_dicts", False)
self.public_baseurl = config.get("public_baseurl")
+ self.cpu_affinity = config.get("cpu_affinity")
# Whether to send federation traffic out in this process. This only
# applies to some federation traffic, and so shouldn't be used to
@@ -147,6 +149,27 @@ class ServerConfig(Config):
# When running as a daemon, the file to store the pid in
pid_file: %(pid_file)s
+ # CPU affinity mask. Setting this restricts the CPUs on which the
+ # process will be scheduled. It is represented as a bitmask, with the
+ # lowest order bit corresponding to the first logical CPU and the
+ # highest order bit corresponding to the last logical CPU. Not all CPUs
+ # may exist on a given system but a mask may specify more CPUs than are
+ # present.
+ #
+ # For example:
+ # 0x00000001 is processor #0,
+ # 0x00000003 is processors #0 and #1,
+ # 0xFFFFFFFF is all processors (#0 through #31).
+ #
+ # Pinning a Python process to a single CPU is desirable, because Python
+ # is inherently single-threaded due to the GIL, and can suffer a
+ # 30-40%% slowdown due to cache blow-out and thread context switching
+ # if the scheduler happens to schedule the underlying threads across
+ # different cores. See
+ # https://www.mirantis.com/blog/improve-performance-python-programs-restricting-single-cpu/.
+ #
+ # cpu_affinity: 0xFFFFFFFF
+
# Whether to serve a web client from the HTTP/HTTPS root resource.
web_client: True
|
