doc/crimson/crimson.rst: introduce Enabling io_uring

We could enable this as part of packaged installs though
letting users enable this explicitly seems like a better approach.

Signed-off-by: Matan Breizman <mbreizma@redhat.com>

diff --git a/doc/crimson/crimson.rst b/doc/crimson/crimson.rst
index 863c160c890da15cc3c10fcc2e63b714903fa3a0..503077b9c71b1c74cbcde253306d2993ce84539a 100644 (file)
--- a/doc/crimson/crimson.rst
+++ b/doc/crimson/crimson.rst
@@ -82,6 +82,18 @@ If the above file is named ``osd-spec.yaml``, it can be used to deploy OSDs like
 
 .. _crimson-cpu-allocation:
 
+Enabling io_uring
+=================
+
+Seastar backend can beneift significantly from Linux's io_uring interface, providing lower latency and higher throughput.
+io_uring is the defualt reactor backend (see `crimson_reactor_backend` option).
+On some conservative distributions, io_uring may be disabled, preventing Crimson from using it.
+If this configuration change is acceptable in your environment, you may enable io_uring support by running:
+
+.. prompt:: bash #
+    sudo sysctl -w kernel.io_uring_disabled=0
+
+
 Crimson CPU allocation
 ======================