From nobody Tue Oct 7 18:27:27 2025 Received: from m16.mail.163.com (m16.mail.163.com [117.135.210.5]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 67D321F63F9; Tue, 8 Jul 2025 05:41:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=117.135.210.5 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751953304; cv=none; b=RyVZwQ4jWecADDRnI/QJyiotScFlC31n05qJdvUd7I5FwrG5p7tcJY1x+OgrKGiQHpZu/pvqb7zo4OJLyz6q8jNc9qln4HlgRE/3X/npl0j7joHAlfVBkPJ0EVk4ZQSysO1lbA8kCJc1zhGKbe1T3LJWJDlxIYIbZYQtH2+l3y0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751953304; c=relaxed/simple; bh=U91KJJNvviR0er8DdpJrBD+Tr8HIK+EjbsXrdILrQaA=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=o2LO2kWFkXP+TxznoO7zma8MDpVVsCziSG1tC6zdNbjV2COY95buGqfaRemia9DGWjgko+5tmPG16ls1Chbw50TZONDiJj9bwtTRYrl82AC4C9u7xfzzTax0wsNzXEk48JVjJx2Ot8K6BYZKMuq1z56EoENlsUA6sC1TriqT0rE= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com; spf=pass smtp.mailfrom=163.com; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b=e/EICdqe; arc=none smtp.client-ip=117.135.210.5 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=163.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=163.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=163.com header.i=@163.com header.b="e/EICdqe" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=163.com; s=s110527; h=From:To:Subject:Date:Message-Id:MIME-Version; bh=hB 9+b1LD8EAuIVyKEZhY6u3hXYecNCPzItwCce/1pNU=; b=e/EICdqeC9dOLWPRUY wtnCcM3upFl86bf8S7XCHH2afUyXYtRX41OQYO8rVDu54o0EfC36hT4U++Is9XUs b3iKsdHESRkoO1HFE5Vr+rwyg+bTn7cq2jE/lwsVNyt4CAuCGbQ4CCzAb/zUJ+qH PZd49oIMo5DYdq7LhwLUevn7U= Received: from localhost.localdomain (unknown []) by gzga-smtp-mtada-g1-2 (Coremail) with SMTP id _____wDX7zVmr2xoBK_ADQ--.22627S2; Tue, 08 Jul 2025 13:40:55 +0800 (CST) From: Feng Yang To: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, willemb@google.com, almasrymina@google.com, kerneljasonxing@gmail.com, ebiggers@google.com, asml.silence@gmail.com, aleksander.lobakin@intel.com, stfomichev@gmail.com, david.laight.linux@gmail.com Cc: yangfeng@kylinos.cn, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH v4] skbuff: Add MSG_MORE flag to optimize tcp large packet transmission Date: Tue, 8 Jul 2025 13:40:53 +0800 Message-Id: <20250708054053.39551-1-yangfeng59949@163.com> X-Mailer: git-send-email 2.25.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-CM-TRANSID: _____wDX7zVmr2xoBK_ADQ--.22627S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7AF1rCry8tr1fZry7CrW5Awb_yoW8uw1kpF Z8Wa98uF47Xw18WFs3G39xur42qan5GFyxKFs5Z343Jr9Fqr18WrW8Kr4YvFsYgrs7CF43 Zr4qvF17KFWUZaDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07UZzVnUUUUU= X-CM-SenderInfo: p1dqww5hqjkmqzuzqiywtou0bp/1tbipQeEeGhsrdEwcwAAsl Content-Type: text/plain; charset="utf-8" From: Feng Yang When using sockmap for forwarding, the average latency for different packet= sizes after sending 10,000 packets is as follows: size old(us) new(us) 512 56 55 1472 58 58 1600 106 81 3000 145 105 5000 182 125 Suggested-by: Eric Dumazet Signed-off-by: Feng Yang Reviewed-by: Eric Dumazet --- Changes in v4: - limiting MSG_MORE hint to TCP. Thanks: Paolo Abeni, David Laight, Eric Du= mazet. - Link to v3: https://lore.kernel.org/all/20250630071029.76482-1-yangfeng59= 949@163.com/ Changes in v3: - Use Msg_MORE flag. Thanks: Eric Dumazet, David Laight. - Link to v2: https://lore.kernel.org/all/20250627094406.100919-1-yangfeng5= 9949@163.com/ Changes in v2: - Delete dynamic memory allocation, thanks: Paolo Abeni,Stanislav Fomichev. - Link to v1: https://lore.kernel.org/all/20250623084212.122284-1-yangfeng5= 9949@163.com/ --- net/core/skbuff.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 85fc82f72d26..b8da621f1552 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -3235,6 +3235,7 @@ typedef int (*sendmsg_func)(struct sock *sk, struct m= sghdr *msg); static int __skb_send_sock(struct sock *sk, struct sk_buff *skb, int offse= t, int len, sendmsg_func sendmsg, int flags) { + int more_hint =3D sk_is_tcp(sk) ? MSG_MORE : 0; unsigned int orig_len =3D len; struct sk_buff *head =3D skb; unsigned short fragidx; @@ -3252,6 +3253,8 @@ static int __skb_send_sock(struct sock *sk, struct sk= _buff *skb, int offset, kv.iov_len =3D slen; memset(&msg, 0, sizeof(msg)); msg.msg_flags =3D MSG_DONTWAIT | flags; + if (slen < len) + msg.msg_flags |=3D more_hint; =20 iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, &kv, 1, slen); ret =3D INDIRECT_CALL_2(sendmsg, sendmsg_locked, @@ -3292,6 +3295,8 @@ static int __skb_send_sock(struct sock *sk, struct sk= _buff *skb, int offset, flags, }; =20 + if (slen < len) + msg.msg_flags |=3D more_hint; bvec_set_page(&bvec, skb_frag_page(frag), slen, skb_frag_off(frag) + offset); iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1, --=20 2.43.0