soreuseport: TCP/IPv4 implementation

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Allow multiple listener sockets to bind to the same port.

Motivation for soresuseport would be something like a web server
binding to port 80 running with multiple threads, where each thread
might have it's own listener socket.  This could be done as an
alternative to other models: 1) have one listener thread which
dispatches completed connections to workers. 2) accept on a single
listener socket from multiple threads.  In case #1 the listener thread
can easily become the bottleneck with high connection turn-over rate.
In case #2, the proportion of connections accepted per thread tends
to be uneven under high connection load (assuming simple event loop:
while (1) { accept(); process() }, wakeup does not promote fairness
among the sockets.  We have seen the  disproportion to be as high
as 3:1 ratio between thread accepting most connections and the one
accepting the fewest.  With so_reusport the distribution is
uniform.

Signed-off-by: Tom Herbert <therbert@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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Tom Herbert 2013-01-22 09:50:24 +00:00 • committed by David S. Miller

parent 055dc21a1d

commit da5e36308d

5 changed files with 73 additions and 21 deletions

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13

include/net/inet_hashtables.h

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1

include/net/netfilter/nf_tproxy_core.h

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48

net/ipv4/inet_connection_sock.c

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28

net/ipv4/inet_hashtables.c

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4

net/ipv4/tcp_ipv4.c

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