On Mon, Jan 20, 2025 at 06:26:36PM +0100, Stefano Brivio wrote:

...so it's pointless to set SO_RCVBUF and SO_SNDBUF on listening sockets.

Call tcp_sock_set_bufsize() after accept4(), for inbound sockets.

As we didn't have large buffer sizes set for inbound sockets for a long time (they are set explicitly only if the maximum size is big enough, more than than the ~200 KiB default), I ran some more throughput tests for this one, and I see slightly better numbers (say, 17 gbps instead of 15 gbps guest to host without vhost-user).

Fixes: 904b86ade7db ("tcp: Rework window handling, timers, add SO_RCVLOWAT and pools for sockets/pipes") Signed-off-by: Stefano Brivio

Reviewed-by: David Gibson

--- tcp.c | 11 ++++------- 1 file changed, 4 insertions(+), 7 deletions(-)

diff --git a/tcp.c b/tcp.c index 3b3193a..a012b81 100644 --- a/tcp.c +++ b/tcp.c @@ -2057,6 +2057,8 @@ void tcp_listen_handler(const struct ctx *c, union epoll_ref ref, if (s < 0) goto cancel;

+ tcp_sock_set_bufsize(c, s); + /* FIXME: When listening port has a specific bound address, record that * as our address */ @@ -2260,7 +2262,6 @@ static int tcp_sock_init_one(const struct ctx *c, const union inany_addr *addr, if (s < 0) return s;

- tcp_sock_set_bufsize(c, s); return s; }

@@ -2317,9 +2318,7 @@ static void tcp_ns_sock_init4(const struct ctx *c, in_port_t port)

s = pif_sock_l4(c, EPOLL_TYPE_TCP_LISTEN, PIF_SPLICE, &inany_loopback4, NULL, port, tref.u32); - if (s >= 0) - tcp_sock_set_bufsize(c, s); - else + if (s < 0) s = -1;

if (c->tcp.fwd_out.mode == FWD_AUTO) @@ -2343,9 +2342,7 @@ static void tcp_ns_sock_init6(const struct ctx *c, in_port_t port)

s = pif_sock_l4(c, EPOLL_TYPE_TCP_LISTEN, PIF_SPLICE, &inany_loopback6, NULL, port, tref.u32); - if (s >= 0) - tcp_sock_set_bufsize(c, s); - else + if (s < 0) s = -1;

if (c->tcp.fwd_out.mode == FWD_AUTO)

-- David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson