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 9FA7AE571; Thu, 6 Nov 2025 00:24:31 +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=1762388673; cv=none; b=LRRxlI15tZ2GQjL0n6eDWEx1ZHIysY8ai9ipPHIsogH9Vj4fP29TAeDShaoRJzrBUKJ5Wtw1cXFTTzpxGuku23R+Cnh21CgQUCzrc/6z9WdkMOOGG3tZ+koRIRV3m0R/PQjtnEIZw2oyHf/NYxUoCIANdrpqCUnS+nddhrn+x44= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762388673; c=relaxed/simple; bh=cyoWoWBVCUlnvIKaD2wnyG3BjdQVmpDpVXxUsc24x7o=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=NjLFBaRd0qgIn9kyJxgU87QUWw6UvF7KGL+Hp0k0Qw3xJ/ytfdLav2YEftzO3DyYRcyh+WCxT2lTdKGnGfWit/dDkrU3LvQ0KArSYC1pgaSfFNRrhX2rCaSfB/DhMoxZ+IMKnbuDoibGdj3Wey84PiFj1HN1ro2jPgGGuFTi3Tg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=GKi1X5tb; 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="GKi1X5tb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B8D41C4CEF8; Thu, 6 Nov 2025 00:24:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1762388671; bh=cyoWoWBVCUlnvIKaD2wnyG3BjdQVmpDpVXxUsc24x7o=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=GKi1X5tbxCEitNKwd6eWSQZ5S8zSKsVgxy8lbvQUgxzXq+YFCY6wucgtNAIJYJ36n 39ZLyikSr7UYQOJu0sJGaYaX2sqDBaoZYOuLERL7JCrh5cUzqkA3j4vwqxsfBjPfUd 5z6IYCr0PAs2pEN6YYP3SCCGJpM80+SjD0DU6+DNH3CtsfmLjtLV/XY0WPv64t9BCJ PyY7GN54gyjuGja3n06/Zc7LraGIpJ7fdYdPxknTxPKPbRJTkdzNi0l/JiLFUs/Zzl nRXEGBH8XL9Q1kD4uZ6pRsXAlUKCCApFGWfJmAOXlRU0UXEHjc0mtS5ynFz8Z+3CxV On90OxzbhbuSQ== Date: Wed, 5 Nov 2025 16:24:29 -0800 From: Jakub Kicinski To: Wen Gu 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 Subject: Re: [PATCH net-next v5 1/2] ptp: introduce Alibaba CIPU PHC driver Message-ID: <20251105162429.37127978@kernel.org> In-Reply-To: <8a74f801-1de5-4a1d-adc7-66a91221485d@linux.alibaba.com> 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> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit 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. 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. > > 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.