From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id BE3FCC433EF for ; Mon, 7 Mar 2022 14:24:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S243151AbiCGOZH (ORCPT ); Mon, 7 Mar 2022 09:25:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35290 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S243163AbiCGOZF (ORCPT ); Mon, 7 Mar 2022 09:25:05 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id 28A5C79392 for ; Mon, 7 Mar 2022 06:24:09 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1646663048; 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: in-reply-to:in-reply-to:references:references; bh=cppypvAs3psbfXolygHDRONBSorAINZdMrPRXwq2/qI=; b=TuGyyv5bUq5Ut3sCaM9t33h7hDlsB4P1xUT8DLAqu3fJfBKBAFbCPyPxOQGdLzrxWPeCia EF38n8hhxFaXZnkiZ5cRfJCuwBSK3z7ugh5Bh5u2uqTGAua1iVz/TPg3WU9TOcPa5hsgv8 Yq6oxgAf7trGUMPKU0pgDCpPbcn0ciY= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-600-nCAFmBz_P_2Vmjg300j0Sw-1; Mon, 07 Mar 2022 09:24:04 -0500 X-MC-Unique: nCAFmBz_P_2Vmjg300j0Sw-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A490A1006AAA; Mon, 7 Mar 2022 14:24:02 +0000 (UTC) Received: from localhost (unknown [10.43.135.229]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 967081038AAA; Mon, 7 Mar 2022 14:24:00 +0000 (UTC) Date: Mon, 7 Mar 2022 15:23:58 +0100 From: Miroslav Lichvar To: Richard Cochran Cc: Michael Walle , gerhard@engleder-embedded.com, davem@davemloft.net, kuba@kernel.org, netdev@vger.kernel.org, vinicius.gomes@intel.com, yangbo.lu@nxp.com Subject: Re: [RFC PATCH net-next 0/6] ptp: Support hardware clocks with additional free running time Message-ID: References: <20220306085658.1943-1-gerhard@engleder-embedded.com> <20220307120751.3484125-1-michael@walle.cc> <20220307140531.GA29247@hoboy.vegasvil.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220307140531.GA29247@hoboy.vegasvil.org> X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Mar 07, 2022 at 06:05:31AM -0800, Richard Cochran wrote: > On Mon, Mar 07, 2022 at 01:07:51PM +0100, Michael Walle wrote: > > Richard Cochran wrote: > > > You are adding eight bytes per frame for what is arguably an extreme > > > niche case. > > > > I don't think it is a niche case, btw. I was always wondering why > > NXP introduced the vclock thingy. And apparently it is for ... > > Niche is relative. > > Believe it or not, the overwhelmingly great majority of people using > Linux have no interest in TSN. Is this not the same issue as what was recently discussed about some devices being able to provide two (e.g. PHY+MAC) or even more timestamps at the same time? There is a need to have multiple PHCs per device and for that to work the drivers need to be able to save multiple timestamps per packet. In this series it is an additional freerunning clock. That seems too specific. I think we need a more general approach that will support two and more physical PHCs per device. Virtual clocks are not involved here. -- Miroslav Lichvar