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author | Eric Dumazet <edumazet@google.com> | 2015-02-06 12:59:01 -0800 |
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committer | David S. Miller <davem@davemloft.net> | 2015-02-08 16:53:57 -0800 |
commit | 567e4b79731c352a17d73c483959f795d3593e03 (patch) | |
tree | 4af65c205a8b65cfc5fd7b42e7b8750728230616 /net/ipv4/af_inet.c | |
parent | 096a4cfa5807aa89c78ce12309c0b1c10cf88184 (diff) | |
download | linux-567e4b79731c352a17d73c483959f795d3593e03.tar.gz linux-567e4b79731c352a17d73c483959f795d3593e03.tar.bz2 linux-567e4b79731c352a17d73c483959f795d3593e03.zip |
net: rfs: add hash collision detection
Receive Flow Steering is a nice solution but suffers from
hash collisions when a mix of connected and unconnected traffic
is received on the host, when flow hash table is populated.
Also, clearing flow in inet_release() makes RFS not very good
for short lived flows, as many packets can follow close().
(FIN , ACK packets, ...)
This patch extends the information stored into global hash table
to not only include cpu number, but upper part of the hash value.
I use a 32bit value, and dynamically split it in two parts.
For host with less than 64 possible cpus, this gives 6 bits for the
cpu number, and 26 (32-6) bits for the upper part of the hash.
Since hash bucket selection use low order bits of the hash, we have
a full hash match, if /proc/sys/net/core/rps_sock_flow_entries is big
enough.
If the hash found in flow table does not match, we fallback to RPS (if
it is enabled for the rxqueue).
This means that a packet for an non connected flow can avoid the
IPI through a unrelated/victim CPU.
This also means we no longer have to clear the table at socket
close time, and this helps short lived flows performance.
Signed-off-by: Eric Dumazet <edumazet@google.com>
Acked-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/ipv4/af_inet.c')
-rw-r--r-- | net/ipv4/af_inet.c | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/net/ipv4/af_inet.c b/net/ipv4/af_inet.c index a44773c8346c..d2e49baaff63 100644 --- a/net/ipv4/af_inet.c +++ b/net/ipv4/af_inet.c @@ -395,8 +395,6 @@ int inet_release(struct socket *sock) if (sk) { long timeout; - sock_rps_reset_flow(sk); - /* Applications forget to leave groups before exiting */ ip_mc_drop_socket(sk); |