From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) (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 BD86E156C69 for ; Wed, 14 May 2025 07:13:15 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=170.10.129.124 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747206798; cv=none; b=Uz3H5+r6R0FS2iwyk1oVpE+ZIXAZIkhKfc/Cu2zLFQgGNJOAY+zUbQozs89jYeJ9lD6M6isKj89J1MIDmFMV/7oBwPr58Q+Rp8XG0j6uda1skaM1qbQqyXDmyVSu/RBihXbH+7SLMAOdOSm1t3OjWzWyzmQ09xw7MHFE1lwYqdQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1747206798; c=relaxed/simple; bh=2eIWOxcrNRhqnbnz2MbAjnSYx4Blh7k/OlokBmu07Jk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=sQQKyqcJ+QGvYSaXhq67lRvtSLwsq/f0ruBOB2dm+z4pIXo7H09VN81K4we9ttQZaQYHyU7ZE9qQZ2sJ8DkD1Bt/vywHsTpjDb86uFB8OmwGqoh1KX7DtMKCPtvfRuQH81rMf7yl95222/6AK2/Dd6BIR4CX8GYYvMgbY3WiCHI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com; spf=pass smtp.mailfrom=redhat.com; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b=aVR/tEoN; arc=none smtp.client-ip=170.10.129.124 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=redhat.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=redhat.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="aVR/tEoN" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1747206794; 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=AUOZl6lxMjQuCh8vJjhRRDeN8hH1et3Rm9US7z/HtV0=; b=aVR/tEoNrOJKP6EG53ZQhc4J7EHDqHgg+DQEOM77F1SJsuhk2sUWsJH+AcEEAD3yHQrVkR r0yx3OJIKBReG9qML+bUnFUioksdmiKB/+sH6wUBFzPH19HO5kQXzWxBA4B+CqrGDuz0Ri SksTxfP0B079Y8FC/vtZNI0l1Xa7YUE= Received: from mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-31-eYDFsvi4Nq2FH8OQdLYpoA-1; Wed, 14 May 2025 03:13:09 -0400 X-MC-Unique: eYDFsvi4Nq2FH8OQdLYpoA-1 X-Mimecast-MFC-AGG-ID: eYDFsvi4Nq2FH8OQdLYpoA_1747206787 Received: from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-08.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id F316618004A7; Wed, 14 May 2025 07:13:06 +0000 (UTC) Received: from localhost (unknown [10.43.135.229]) by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 0454A1940E95; Wed, 14 May 2025 07:13:01 +0000 (UTC) Date: Wed, 14 May 2025 09:12:59 +0200 From: Miroslav Lichvar To: Thomas Gleixner Cc: LKML , netdev@vger.kernel.org, Richard Cochran , Christopher Hall , David Zage , John Stultz , Frederic Weisbecker , Anna-Maria Behnsen , Werner Abt , David Woodhouse , Stephen Boyd , Thomas =?iso-8859-1?Q?Wei=DFschuh?= , Kurt Kanzenbach , Nam Cao , Alex Gieringer Subject: Re: [patch 00/26] timekeeping: Provide support for independent PTP timekeepers Message-ID: References: <20250513144615.252881431@linutronix.de> 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-Disposition: inline In-Reply-To: <20250513144615.252881431@linutronix.de> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.17 On Tue, May 13, 2025 at 05:12:54PM +0200, Thomas Gleixner wrote: > This series addresses the timekeeping part by utilizing the existing > timekeeping and NTP infrastructure, which has been prepared for > multi-instance in recent kernels. This looks very interesting. I ran some quick tests and it seems to work as expected from the user space point of view. I can enable the clock and synchronize it to a PTP HW clock or the system REALTIME clock. ADJ_TICK works too. To get accuracy and stability comparable to CLOCK_REALTIME, there will need to be some support for cross timestamping against CLOCK_REALTIME and/or PTP HW clocks, e.g. a variant of the PTP_SYS_OFFSET_PRECISE and PTP_SYS_OFFSET_EXTENDED ioctls where the target clock can be selected. The "PTP" naming of these new clocks doesn't seem right to me though and I suspect it would just create more confusion. I don't see anything specific to PTP here. There is no timestamping of network packets, no /dev/ptp device, no PTP ioctls. To me they look like secondary or auxiliary system realtime clocks. I propose to rename them from CLOCK_PTP0-7 to CLOCK_REALTIME2-9, CLOCK_AUXILIARY0-7, or CLOCK_AUX0-7. -- Miroslav Lichvar