From mboxrd@z Thu Jan 1 00:00:00 1970 Received: by passt.top (Postfix, from userid 1000) id 072FA5A061B; Mon, 20 Jan 2025 18:26:36 +0100 (CET) From: Stefano Brivio To: passt-dev@passt.top Subject: [PATCH] tcp: Buffer sizes are *not* inherited on accept()/accept4() Date: Mon, 20 Jan 2025 18:26:36 +0100 Message-ID: <20250120172636.2102207-1-sbrivio@redhat.com> X-Mailer: git-send-email 2.43.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-ID-Hash: TMWDH6U4HKO53WZTT2PGZTTBNTZ6DDT6 X-Message-ID-Hash: TMWDH6U4HKO53WZTT2PGZTTBNTZ6DDT6 X-MailFrom: sbrivio@passt.top X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: David Gibson X-Mailman-Version: 3.3.8 Precedence: list List-Id: Development discussion and patches for passt Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: ...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 --- 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) -- 2.43.0