tree 69b0d3d0619f70911f9dee2b98bbc9072fc14b50
parent 3b20fc389705a4c959adebc494578cb99bb8be9e
author Sowmini Varadhan <sowmini.varadhan@oracle.com> 1443646448 -0400
committer David S. Miller <davem@davemloft.net> 1444041293 -0700

RDS-TCP: Do not bloat sndbuf/rcvbuf in rds_tcp_tune

Using the value of RDS_TCP_DEFAULT_BUFSIZE (128K)
clobbers efficient use of TSO because it inflates the size_goal
that is computed in tcp_sendmsg/tcp_sendpage and skews packet
latency, and the default values for these parameters actually
results in significantly better performance.

In request-response tests using rds-stress with a packet size of
100K with 16 threads (test parameters -q 100000 -a 256 -t16 -d16)
between a single pair of IP addresses achieves a throughput of
6-8 Gbps. Without this patch, throughput maxes at 2-3 Gbps under
equivalent conditions on these platforms.

Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>