Commit 2dc41cff authored by Committed by David S. MillerBrowse files
udp: Use hash2 for long hash1 chains in __udp*_lib_mcast_deliver.
Many multicast sources can have the same port which can result in a very large list when hashing by port only. Hash by address and port instead if this is the case. This makes multicast more similar to unicast. On a 24-core machine receiving from 500 multicast sockets on the same port, before this patch 80% of system CPU was used up by spin locking and only ~25% of packets were successfully delivered. With this patch, all packets are delivered and kernel overhead is ~8% system CPU on spinlocks. Signed-off-by: David Held <email@example.com> Signed-off-by: Eric Dumazet <firstname.lastname@example.org> Signed-off-by: David S. Miller <email@example.com>