From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 1023245107A; Mon, 18 May 2026 13:01:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779109291; cv=none; b=W+0d6HhsFaOSAdA00ySI1BUsWKNlZp9eNuTyH+o9ycqtseiqDfXpWHOXw1czkWY4DgYfyCqZKjvBxtqVi7ODhIkpAQ7OpAVKLESGKtVUgWPNb1G1TLmRpkDFROmZD3L7LQHXe8lAvzLv+iFeu0p13GmSpWRX5ufMrfPj6F18BNE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779109291; c=relaxed/simple; bh=hojHRr+PheKoQ7m5OKEUeo0v+iLPsIfkBZlaT1Myalg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=rQwFOZUhGGXkaDVwEdlNd97JopeBadvFFeNBtK7UosozmUWAfrQmxA2SaX290/06JIOiM2N04oLbgUpHOl9IB+VRF55F7kHwAh3jmMqO/NH4Gw2TtqIx0KAp06vxVVnMg9pN8YjccY5Ss0WcXVhKuy0HkNsAUR1COfS3ggRMAAk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=iCkNx4CO; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="iCkNx4CO" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 36914C2BCB7; Mon, 18 May 2026 13:01:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1779109290; bh=hojHRr+PheKoQ7m5OKEUeo0v+iLPsIfkBZlaT1Myalg=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=iCkNx4COB7SMaKeftGoydd9hWGfaLWmMcABqSc/aDRmNTLoszje2E78szvbBWyGOF fY0oHcTNfwEHadVc2//53yGKZ+4JLrOVIEqxyHhbFYyolq/T+Wcnm8Z1TBz3OUEO0f 4JwIS+dtdmoOcxLge3kMaDgrGq3Y1IwNS4nAG+6GMZr6gvcfzmVqNPFhYjnrLJgl5B eikuxuVBGsHT7MECuGfR1ri0vU8DY6RS6/1WQ3eGaQobkRjyA+ijYvSnTn01IOQ2eq CoV1OInrdeR8/8erKc8ose8yipMm+grip2W5tohSMzhwkzx7qsTgvkYfqynMGZ7z8l W3hEgd3Oz2wgg== Message-ID: Date: Mon, 18 May 2026 15:01:22 +0200 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net-next 5/6] bpf: enable bpf timestamping rx in TCP layer To: Jason Xing , davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, horms@kernel.org, willemb@google.com, kuniyu@google.com, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, martin.lau@linux.dev, eddyz87@gmail.com, memxor@gmail.com, song@kernel.org, yonghong.song@linux.dev, jolsa@kernel.org, john.fastabend@gmail.com, sdf@fomichev.me, Simon Sundberg , =?UTF-8?B?VG9rZSBIw7hpbGFuZC1Kw7hy?= =?UTF-8?Q?gensen?= Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, Jason Xing References: <20260518082344.96647-1-kerneljasonxing@gmail.com> <20260518082344.96647-6-kerneljasonxing@gmail.com> Content-Language: en-US From: Jesper Dangaard Brouer In-Reply-To: <20260518082344.96647-6-kerneljasonxing@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 18/05/2026 10.23, Jason Xing wrote: > From: Jason Xing > > Add two if statements to accurately isolate bpf timestamping and so > timestamping. They can work respectively. > > As to so_timestamping, only add a loose condition via report flags > to avoid duplicate strict checks that is done in tcp_recv_timestamp() > and performance impact. If the loose condition is hit, > tcp_recv_timestamp() is able to handle the exact case and doesn't > hamper the existing timestamping feature. > > Make it work in TCP protocol. > > Signed-off-by: Jason Xing > --- > net/ipv4/tcp.c | 14 ++++++++++++-- > 1 file changed, 12 insertions(+), 2 deletions(-) > > diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c > index 21ece4c71612..64c69bb3578a 100644 > --- a/net/ipv4/tcp.c > +++ b/net/ipv4/tcp.c > @@ -2949,8 +2949,18 @@ int tcp_recvmsg(struct sock *sk, struct msghdr *msg, size_t len, int flags) > release_sock(sk); > > if ((cmsg_flags | msg->msg_get_inq) && ret >= 0) { > - if (cmsg_flags & TCP_CMSG_TS) > - tcp_recv_timestamp(msg, sk, &tss); > + if (cmsg_flags & TCP_CMSG_TS) { > + u32 tsflags = READ_ONCE(sk->sk_tsflags); > + > + if (cgroup_bpf_enabled(CGROUP_SOCK_OPS) && > + SK_BPF_CB_FLAG_TEST(sk, SK_BPF_CB_RX_TIMESTAMPING)) > + bpf_skops_rx_timestamping(sk, &tss, > + BPF_SOCK_OPS_TSTAMP_RCV_CB); Does this mean I can enable timestamp reading per cgroup? In Simon's netstacklat[1] tool we are forced process all RX timestamp (hooking fentry/tcp_recv_timestamp), and then we have a BPF filter[2] on the cgroup IDs that we are interested in (which is a significant overhead, as this is deployed at Cloudflare production scale). [1] https://github.com/xdp-project/bpf-examples/tree/main/netstacklat [2] https://github.com/xdp-project/bpf-examples/blob/main/netstacklat/netstacklat.bpf.c#L484-L488 > + if (sock_flag(sk, SOCK_RCVTSTAMP) || > + tsflags & SOF_TIMESTAMPING_SOFTWARE || > + tsflags & SOF_TIMESTAMPING_RAW_HARDWARE) > + tcp_recv_timestamp(msg, sk, &tss); > + } > if ((cmsg_flags & TCP_CMSG_INQ) | msg->msg_get_inq) { > msg->msg_inq = tcp_inq_hint(sk); > if (cmsg_flags & TCP_CMSG_INQ)