From nobody Wed Oct 8 10:02:27 2025 Received: from m16.mail.163.com (m16.mail.163.com [117.135.210.5]) by smtp.subspace.kernel.org (Postfix) with ESMTP id C443621ABB1; Mon, 30 Jun 2025 07:11:25 +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=1751267489; cv=none; b=uVaD5+kndoneFYO27zKge8uvNtq9e7Jzzmy37YcOSR/xWQbGZ2b60DEm6LuWv9ktg8jYOHajRCPw2KJcYV7C04Od5Drj585YMLTzYHAUIFa5oaWHtSshUbofoaeY99MCfuzLgo5a5npMn5H8XFYB7M/fMpvSRjB/xpjchoj9K+E= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1751267489; c=relaxed/simple; bh=aLJ5Fh7woyj6lcXkF33z0s0wIaI2PABc4me1NR5K6wA=; h=From:To:Cc:Subject:Date:Message-Id:MIME-Version; b=EUF5PS8AY9N2Kdpkmxh18RIupzyNPNCVOx6P2pC1JDUxlxavCouFHKuP9Eb2ae/F7eGbBtGl8MJyYjH2k5ZbELC5j44zhLoCzVWfcRHqM/6e71qmePuspX9DRWKonZaAVqpHWA2tx9vFJkL0ejwzt7jvdBwcevdEpP97bpBJtRQ= 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=iPbGolaQ; 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="iPbGolaQ" 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=mq +lCN5C85/urD5+hhWk5hPE/mDa4QuDWCpfswWybYs=; b=iPbGolaQYSsX2LY5Lg YeS8LyytWOVYe7IWNc/iQ19vSx6etOz9qnODdMMDIC3dj8YApUId4XvKbmENke6w a0saHNE93OvkVY4S6H5heKlRk1iRoTZX+5RWGUFcyMOaWXcts+6vmpO8r1R68CWh 7xakozcZpQdUraaw6f2ruoRvA= Received: from localhost.localdomain (unknown []) by gzga-smtp-mtada-g0-4 (Coremail) with SMTP id _____wDHzzBlOGJoS3s5Bg--.7606S2; Mon, 30 Jun 2025 15:10:30 +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 v3] skbuff: Add MSG_MORE flag to optimize large packet transmission Date: Mon, 30 Jun 2025 15:10:29 +0800 Message-Id: <20250630071029.76482-1-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: _____wDHzzBlOGJoS3s5Bg--.7606S2 X-Coremail-Antispam: 1Uf129KBjvJXoW7KF17tFyktw15CFyrXF1UKFg_yoW8Aw1kpa 98WFWDZF47Jw13WFs7Jws8ur47Kws5GFyj9FWYv345GasFqr1vgrWDKrWYvFs5KrZ7CFy3 XrsFvF1UK3yYvaDanT9S1TB71UUUUU7qnTZGkaVYY2UrUUUUjbIjqfuFe4nvWSU5nxnvy2 9KBjDUYxBIdaVFxhVjvjDU0xZFpf9x07UZiSLUUUUU= X-CM-SenderInfo: p1dqww5hqjkmqzuzqiywtou0bp/1tbiTg98eGhiNtQyRwAAsY Content-Type: text/plain; charset="utf-8" From: Feng Yang The "MSG_MORE" flag is added to improve the transmission performance of lar= ge packets. The improvement is more significant for TCP, while there is a slight enhanc= ement for UDP. When using sockmap for forwarding, the average latency for different packet= sizes after sending 10,000 packets(TCP) 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 --- 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 | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/net/core/skbuff.c b/net/core/skbuff.c index 85fc82f72d26..cd1ed96607a5 100644 --- a/net/core/skbuff.c +++ b/net/core/skbuff.c @@ -3252,6 +3252,8 @@ 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 MSG_MORE; =20 iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, &kv, 1, slen); ret =3D INDIRECT_CALL_2(sendmsg, sendmsg_locked, @@ -3292,6 +3294,8 @@ static int __skb_send_sock(struct sock *sk, struct sk= _buff *skb, int offset, flags, }; =20 + if (slen < len) + msg.msg_flags |=3D MSG_MORE; 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