From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out30-118.freemail.mail.aliyun.com (out30-118.freemail.mail.aliyun.com [115.124.30.118]) (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 2D1E52222C8; Thu, 27 Nov 2025 05:48:56 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=115.124.30.118 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764222539; cv=none; b=sBVMKAnkiCpQ7osFLPZeIIkZ1HGRf3u/8lf7j2aHceWPoYUkKKARud4GFgsM0c/eKOlIOWDrL73TLQin96bFfGQQMVw7agmeotNvd6KE7PcSQH87XwZmBjzzAYUx6U8+6Sj2V7Jy5dWcDCcW/e96+/OG4VJwAvKUVQBUBwWfjkE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1764222539; c=relaxed/simple; bh=Py2YiWs8cF5O0eUyYLj1hK4QFKhPEbxIeYOJ3hkCibs=; h=Message-ID:Date:MIME-Version:From:Subject:To:Cc:References: In-Reply-To:Content-Type; b=qq2Udv6FNJsqWS4g7Z80oramf9pLNa/weI5gKPA2lHbV8v9VDYacYOx4irjCjMKlLaCTnm9jXH1lxne7PiaTgZRtOW6/+XwBW6Tf1Q71YrIsRBbkyF/InFfgQOf71naNom7jQ6p+Y0HKdoDXiHexRP4KX2JoBeWWmNag9B9a36k= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com; spf=pass smtp.mailfrom=linux.alibaba.com; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b=D/lHJoiu; arc=none smtp.client-ip=115.124.30.118 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.alibaba.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.alibaba.com header.i=@linux.alibaba.com header.b="D/lHJoiu" DKIM-Signature:v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.alibaba.com; s=default; t=1764222529; h=Message-ID:Date:MIME-Version:From:Subject:To:Content-Type; bh=CY0MUl2egl6z58i2a4LkDtU35iyhPW0STYeV0S/ftNQ=; b=D/lHJoiuwQ4ScjFYzvke5/OQVhgl/zzxKJqbY/Mw5kbTSbpu8tkCfxVQDZVYqJmpj0MONadOMRajs0ulX4Ayz7e43tZgOsTO8S30E6psFt499mtWFZJmyPZcF62t9qwhU9hNKF9Qu2al1cD9KUILiVFITpM9psTyxS9xoZ/nejY= Received: from 30.221.144.80(mailfrom:guwen@linux.alibaba.com fp:SMTPD_---0WtVusyr_1764222527 cluster:ay36) by smtp.aliyun-inc.com; Thu, 27 Nov 2025 13:48:48 +0800 Message-ID: <34b30157-6d67-46ec-abde-da9087fbf318@linux.alibaba.com> Date: Thu, 27 Nov 2025 13:48:47 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird From: Wen Gu Subject: Re: [PATCH net-next v5 1/2] ptp: introduce Alibaba CIPU PHC driver To: Jakub Kicinski Cc: richardcochran@gmail.com, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, pabeni@redhat.com, xuanzhuo@linux.alibaba.com, dust.li@linux.alibaba.com, netdev@vger.kernel.org, linux-kernel@vger.kernel.org References: <20251030121314.56729-1-guwen@linux.alibaba.com> <20251030121314.56729-2-guwen@linux.alibaba.com> <20251031165820.70353b68@kernel.org> <8a74f801-1de5-4a1d-adc7-66a91221485d@linux.alibaba.com> <20251105162429.37127978@kernel.org> In-Reply-To: <20251105162429.37127978@kernel.org> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit On 2025/11/6 08:24, Jakub Kicinski wrote: > On Wed, 5 Nov 2025 18:22:19 +0800 Wen Gu wrote: >> On 2025/11/1 07:58, Jakub Kicinski wrote: >>> On Thu, 30 Oct 2025 20:13:13 +0800 Wen Gu wrote: >>>> This adds a driver for Alibaba CIPU PTP clock. The CIPU, an underlying >>>> infrastructure of Alibaba Cloud, synchronizes time with atomic clocks >>>> via the network and provides microsecond or sub-microsecond precision >>>> timestamps for VMs and bare metals on cloud. >>>> >>>> User space processes, such as chrony, running in VMs or on bare metals >>>> can get the high precision time through the PTP device exposed by this >>>> driver. >>> >>> As mentioned on previous revisions this is a pure clock device which has >>> nothing to do with networking and PTP. >> >> I don't quite agree that this has nothing to do with PTP. >> >> What is the difference between this CIPU PTP driver and other PTP drivers >> under drivers/ptp? such as ptp_s390, ptp_vmw, ptp_pch, and others. Most of >> these PTP drivers do not directly involve IEEE 1588 or networking as well. > Sorry for the late reply due to a vacation. > We can't delete existing drivers. It used to be far less annoying > until every cloud vendor under the sun decided to hack up their own > implementation of something as simple as the clock. > So what kind of drivers do you think are qualified to be placed in the drivers/ptp? I checked some docs, e.g.[1], and codes in drivers/ptp, but I am not sure what the deciding factor is, assuming that exposing a PTP character device is not sufficient. [1] https://docs.kernel.org/driver-api/ptp.html Regards. >>> There should be a separate class >>> for "hypervisor clocks", if not a common driver. >> >> 'hypervisor clock' is not very accurate. CIPU PTP can be used in VM and >> bare metal scenarios, and bare metals do not need hypervisors. > > I know.