From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-176.mta1.migadu.com (out-176.mta1.migadu.com [95.215.58.176]) (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 23D331FB4 for ; Sat, 14 Dec 2024 00:17:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.176 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734135482; cv=none; b=ChUIh+IbyLkV7FwD2Fhg+hHl1FWLHw4K+mG892z9I7uX1ecdyjGzUGUfDOewwc9Btd+cOGzq8/JTPlz2M6r4ZvC+oE5QEs28gTq9bT9MWY/I19UVqEcOXvPoICL3gWShtsANC33OVGYKarfjLEjLDA4kdniiURkZ9E3MYPGkFn0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734135482; c=relaxed/simple; bh=KeCcRhow+86qc5vs4XdC+hiRQ5ec0oSKM6bzbjQ76qY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=HxFy9m3+RGHCKcWQyqMxQq7SEGNylDI3MD5+eeA9XkmnnsaE51IujlHQXIIfpBD36/M7xebwzXev5HdOGqLBAMLgJM+tmHTM2hNRWt2uNvxEdxW7GC7ybg6FFasnowsvssc/ITNIyjzA+M3QGwHauMlY26GM6NkPFmgqR8ugjo8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=FsktCloa; arc=none smtp.client-ip=95.215.58.176 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="FsktCloa" Message-ID: DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1734135477; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=YCAbGUvluC0Y0sru1dCT3kRoMPN5ZbjT6v9S8jGO+Jc=; b=FsktCloaWuCoVCsZvSLcVGeGXkGPWP9RHooHZTtJXDamF8vmPP2W7tDBM0LWqkrwRFdoPZ Xs/pcBc2AIAtf0p6ciSfmI9hJdoHexE+zstRwvm+l6t8c/l2b8YX7hj9vlIZfMAM9mNWuG O6T4juadg/gzgqmqyLGkxn+YhMlBp+4= Date: Fri, 13 Dec 2024 16:17:47 -0800 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Subject: Re: [PATCH net-next v4 07/11] net-timestamp: support hwtstamp print for bpf extension To: Jason Xing Cc: davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, dsahern@kernel.org, willemdebruijn.kernel@gmail.com, willemb@google.com, ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org, eddyz87@gmail.com, song@kernel.org, yonghong.song@linux.dev, john.fastabend@gmail.com, kpsingh@kernel.org, sdf@fomichev.me, haoluo@google.com, jolsa@kernel.org, bpf@vger.kernel.org, netdev@vger.kernel.org, Jason Xing References: <20241207173803.90744-1-kerneljasonxing@gmail.com> <20241207173803.90744-8-kerneljasonxing@gmail.com> <53c3be2f-1d5d-44cb-8c27-18c84bc30c9e@linux.dev> X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Martin KaFai Lau Content-Language: en-US In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Migadu-Flow: FLOW_OUT On 12/13/24 4:02 PM, Jason Xing wrote: > On Sat, Dec 14, 2024 at 7:15 AM Martin KaFai Lau wrote: >> >> On 12/13/24 7:13 AM, Jason Xing wrote: >>>>> -static void __skb_tstamp_tx_bpf(struct sock *sk, struct sk_buff *skb, int tstype) >>>>> +static void __skb_tstamp_tx_bpf(struct sock *sk, struct sk_buff *skb, >>>>> + struct skb_shared_hwtstamps *hwtstamps, >>>>> + int tstype) >>>>> { >>>>> + struct timespec64 tstamp; >>>>> + u32 args[2] = {0, 0}; >>>>> int op; >>>>> >>>>> if (!sk) >>>>> @@ -5552,6 +5556,11 @@ static void __skb_tstamp_tx_bpf(struct sock *sk, struct sk_buff *skb, int tstype >>>>> break; >>>>> case SCM_TSTAMP_SND: >>>>> op = BPF_SOCK_OPS_TS_SW_OPT_CB; >>>>> + if (hwtstamps) { >>>>> + tstamp = ktime_to_timespec64(hwtstamps->hwtstamp); >>>> Avoid this conversion which is likely not useful to the bpf prog. Directly pass >>>> hwtstamps->hwtstamp (in ns?) to the bpf prog. Put lower 32bits in args[0] and >>>> higher 32bits in args[1]. >>> It makes sense. >> >> When replying the patch 2 thread, I noticed it may not even have to pass the >> hwtstamps in args here. >> >> Can "*skb_hwtstamps(skb) = *hwtstamps;" be done before calling the bpf prog? >> Then the bpf prog can directly get it from skb_shinfo(skb)->hwtstamps. >> It is like reading other fields in skb_shinfo(skb), e.g. the >> skb_shinfo(skb)->tskey discussed in patch 10. The bpf prog will have a more >> consistent experience in reading different fields of the skb_shinfo(skb). >> skb_shinfo(skb)->hwtstamps is a more intuitive place to obtain the hwtstamp than >> the broken up args[0] and args[1]. On top of that, there is also an older >> "skb_hwtstamp" field in "struct bpf_sock_ops". > > Right, right, last night, fortunately, I also spotted it. Let the bpf > prog parse the shared info from skb then. A new callback for hwtstamp > is needed, I suppose. Why a new callback is needed? "*skb_hwtstamps(skb) = *hwtstamps;" cannot be done in __skb_tstamp_tx_bpf?