path: root/arch/cris/include/uapi
diff options
authorEric Dumazet <>2014-11-11 05:54:28 -0800
committerDavid S. Miller <>2014-11-11 13:00:06 -0500
commit2c8c56e15df3d4c2af3d656e44feb18789f75837 (patch)
treee3c81c868a7c14ca2bac7efd69b6b21e25c355d4 /arch/cris/include/uapi
parent3d97379a67486bc481ab5b8f7aa5b7ceb6154a95 (diff)
net: introduce SO_INCOMING_CPU
Alternative to RPS/RFS is to use hardware support for multiple queues. Then split a set of million of sockets into worker threads, each one using epoll() to manage events on its own socket pool. Ideally, we want one thread per RX/TX queue/cpu, but we have no way to know after accept() or connect() on which queue/cpu a socket is managed. We normally use one cpu per RX queue (IRQ smp_affinity being properly set), so remembering on socket structure which cpu delivered last packet is enough to solve the problem. After accept(), connect(), or even file descriptor passing around processes, applications can use : int cpu; socklen_t len = sizeof(cpu); getsockopt(fd, SOL_SOCKET, SO_INCOMING_CPU, &cpu, &len); And use this information to put the socket into the right silo for optimal performance, as all networking stack should run on the appropriate cpu, without need to send IPI (RPS/RFS). Signed-off-by: Eric Dumazet <> Signed-off-by: David S. Miller <>
Diffstat (limited to 'arch/cris/include/uapi')
1 files changed, 2 insertions, 0 deletions
diff --git a/arch/cris/include/uapi/asm/socket.h b/arch/cris/include/uapi/asm/socket.h
index ed94e5ed0a23..60f60f5b9b35 100644
--- a/arch/cris/include/uapi/asm/socket.h
+++ b/arch/cris/include/uapi/asm/socket.h
@@ -82,6 +82,8 @@
+#define SO_INCOMING_CPU 49
#endif /* _ASM_SOCKET_H */