This socket option is undocumented. Applies on the latest version (man-pages-4.09-511).
diff --git a/man7/socket.7 b/man7/socket.7 index 3efd7a5d8..1a3ffa253 100644 --- a/man7/socket.7 +++ b/man7/socket.7 @@ -490,6 +490,26 @@ flag on a socket operation. Expects an integer boolean flag. .TP +.BR SO_INCOMING_CPU " (getsockopt since Linux 3.19, setsockopt since Linux 4.4)" +.\" getsocktop 2c8c56e15df3d4c2af3d656e44feb18789f75837 +.\" setsocktop 70da268b569d32a9fddeea85dc18043de9d89f89 +Sets or gets the cpu affinity of a socket. Expects an integer flag. +.sp +.in +4n +.nf +int cpu = 1; +socklen_t len = sizeof(cpu); +setsockopt(fd, SOL_SOCKET, SO_INCOMING_CPU, &cpu, &len); +.fi +.in +.sp +The typical use case is one listener per RX queue, as the associated listener +should only accept flows handled in softirq by the same cpu. This provides +optimal NUMA behavior and keep cpu caches hot. +.TP .B SO_KEEPALIVE Enable sending of keep-alive messages on connection-oriented sockets. Expects an integer boolean flag.
