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authorSoheil Hassas Yeganeh <soheil@google.com>2018-01-03 21:47:11 -0500
committerDavid S. Miller <davem@davemloft.net>2018-01-05 11:14:57 -0500
commit0a38806f31729c8931383d2ce944115312855931 (patch)
tree708cc9eada262ba5ae590aecfab1c8db01ea8814 /net
parentip: do not set RFS core on error queue reads (diff)
downloadlinux-dev-0a38806f31729c8931383d2ce944115312855931.tar.xz
linux-dev-0a38806f31729c8931383d2ce944115312855931.zip
net: revert "Update RFS target at poll for tcp/udp"
On multi-threaded processes, one common architecture is to have one (or a small number of) threads polling sockets, and a considerably larger pool of threads reading form and writing to the sockets. When we set RPS core on tcp_poll() or udp_poll() we essentially steer all packets of all the polled FDs to one (or small number of) cores, creaing a bottleneck and/or RPS misprediction. Another common architecture is to shard FDs among threads pinned to cores. In such a setting, setting RPS core in tcp_poll() and udp_poll() is redundant because the RFS core is correctly set in recvmsg and sendmsg. Thus, revert the following commit: c3f1dbaf6e28 ("net: Update RFS target at poll for tcp/udp"). Signed-off-by: Soheil Hassas Yeganeh <soheil@google.com> Signed-off-by: Willem de Bruijn <willemb@google.com> Signed-off-by: Eric Dumazet <edumazet@google.com> Signed-off-by: Neal Cardwell <ncardwell@google.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r--net/ipv4/tcp.c2
-rw-r--r--net/ipv4/udp.c2
2 files changed, 0 insertions, 4 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 7ac583a2b9fe..f68cb33d50d1 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -498,8 +498,6 @@ unsigned int tcp_poll(struct file *file, struct socket *sock, poll_table *wait)
const struct tcp_sock *tp = tcp_sk(sk);
int state;
- sock_rps_record_flow(sk);
-
sock_poll_wait(file, sk_sleep(sk), wait);
state = inet_sk_state_load(sk);
diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index e9c0d1e1772e..db72619e07e4 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -2490,8 +2490,6 @@ unsigned int udp_poll(struct file *file, struct socket *sock, poll_table *wait)
if (!skb_queue_empty(&udp_sk(sk)->reader_queue))
mask |= POLLIN | POLLRDNORM;
- sock_rps_record_flow(sk);
-
/* Check for false positives due to checksum errors */
if ((mask & POLLRDNORM) && !(file->f_flags & O_NONBLOCK) &&
!(sk->sk_shutdown & RCV_SHUTDOWN) && first_packet_length(sk) == -1)