[RFC PATCH net-next v1 2/2] Documentation: networking: document SO_NO_RFS
flat view
WARM1d
From: Vitaly Zuevsky <hidden>
Date: 2026-10-31 11:33:37
Also in:
linux-arch, linux-doc, linux-mips, lkml, netdev, sparclinux
Subsystem:
documentation, networking [general], the rest · Maintainers:
Jonathan Corbet, "David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
Describe the new per-socket opt-out next to the RFS configuration
knobs it complements.
Signed-off-by: Vitaly Zuevsky <redacted>
---
Documentation/networking/scaling.rst | 14 ++++++++++++++
1 file changed, 14 insertions(+)
diff --git a/Documentation/networking/scaling.rst b/Documentation/networking/scaling.rst
index 6c9836000a8d..54c7a72da563 100644
--- a/Documentation/networking/scaling.rst
+++ b/Documentation/networking/scaling.rst@@ -428,6 +428,20 @@ queues. So for instance, if rps_sock_flow_entries is set to 131072 and there are 16 configured receive queues, rps_flow_cnt for each queue might be configured as 8192. +Excluding individual sockets +~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +RFS (and therefore accelerated RFS, see below) can be switched off for +a single socket with the SO_NO_RFS socket option. Flows of such +sockets are never recorded in rps_sock_flow_table and stay on the CPU +selected by RSS or RPS. The setting is inherited by sockets returned +from accept(), so applying it to a listening socket excludes all +connections accepted from it while connections the same process +initiates with connect() continue to be steered. This is useful when +one host handles both a small set of long-lived flows that benefit +from steering and a large churn of short-lived flows for which the +cost of programming the NIC exceeds the benefit. + Accelerated RFS ===============
--
2.34.1