[rds-devel] [PATCH net-next 2/3] RDS-TCP: Do not bloat sndbuf/rcvbuf in rds_tcp_tune
santosh shilimkar
santosh.shilimkar at oracle.com
Wed Sep 30 08:54:23 PDT 2015
On 9/30/2015 6:45 AM, Sowmini Varadhan wrote:
> 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 at oracle.com>
> ---
> net/rds/tcp.c | 16 ++++------------
> 1 files changed, 4 insertions(+), 12 deletions(-)
>
> diff --git a/net/rds/tcp.c b/net/rds/tcp.c
> index c42b60b..9d6ddba 100644
> --- a/net/rds/tcp.c
> +++ b/net/rds/tcp.c
> @@ -67,21 +67,13 @@ void rds_tcp_nonagle(struct socket *sock)
> set_fs(oldfs);
> }
>
> +/* All module specific customizations to the RDS-TCP socket should be done in
> + * rds_tcp_tune() and applied after socket creation. In general these
> + * customizations should be tunable via module_param()
> + */
> void rds_tcp_tune(struct socket *sock)
> {
> - struct sock *sk = sock->sk;
> -
> rds_tcp_nonagle(sock);
> -
> - /*
> - * We're trying to saturate gigabit with the default,
> - * see svc_sock_setbufsize().
> - */
> - lock_sock(sk);
> - sk->sk_sndbuf = RDS_TCP_DEFAULT_BUFSIZE;
> - sk->sk_rcvbuf = RDS_TCP_DEFAULT_BUFSIZE;
> - sk->sk_userlocks |= SOCK_SNDBUF_LOCK|SOCK_RCVBUF_LOCK;
> - release_sock(sk);
> }
>
> u32 rds_tcp_snd_nxt(struct rds_tcp_connection *tc)
>
We should at least start with sndbuf/rcvbuf parameters.
Nice work. Almost ~3X lift in RDS TCP performance.
Acked-by: Santosh Shilimkar <santosh.shilimkar at oracle.com>
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