From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-fw-52005.amazon.com (smtp-fw-52005.amazon.com [52.119.213.156]) (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 3AD893FE0 for ; Thu, 1 Feb 2024 07:24:55 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=52.119.213.156 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706772297; cv=none; b=hOOc/Sw9dswrr5ZQE5IofPCcodqI3Ao+iIpu9kbMPDim0XkNa3qmNRK7nnbX8m76/VyQoHCU8EzoqZDfZaGzEueGbmmdanxSEqI64pMyoFf/uACbg4nqN5rCxzMB6ZCuBr2eD+GuHg/9Y83VmcDErdFu63xRXj22BF8G1FBCgCM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1706772297; c=relaxed/simple; bh=rt3xdToS1edrEqLARcHH3D4D0bQAx1em8WkrQGW9AHw=; h=From:To:CC:Subject:Date:Message-ID:Content-Type:MIME-Version; b=scVYHmHSuQx7bkpKi3CGIO/Db2FXgWmZPUofejDRfKU8e5uzwx5m81xSHvOyjmO4BK09GfhjjqIX3qOhkF/EsOYUzJ/4r/Vlj6uAFI32XMVtmloXH+09arUF56yFNOf7//fb9WDvaTjbhka7KbE9KMp87sXDlknVjH+a9a8FiuA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com; spf=pass smtp.mailfrom=amazon.com; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b=qqhhIi+H; arc=none smtp.client-ip=52.119.213.156 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=amazon.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=amazon.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=amazon.com header.i=@amazon.com header.b="qqhhIi+H" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazon201209; t=1706772296; x=1738308296; h=from:to:cc:subject:date:message-id: content-transfer-encoding:mime-version; bh=D6B6nIUhDm9/HFTW0ViOh2I+6P+OSFveiy5CYzSjRWY=; b=qqhhIi+HYkEL82FPTRATFtWl1AVBWR+u/p7MuFAXwQ8cSQja/hvvGPum WBwl5TRxnC7aH3PEsNG0oJCAu/40pv7Dsr2oyt4RwfVcb1lirW/rVjjrB N2DyhoFrnwkXw/8oxdWjXNfjL4ktfakmhROwEPJO/sIRFoWY36J5ePxhA o=; X-IronPort-AV: E=Sophos;i="6.05,234,1701129600"; d="scan'208";a="631270136" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO smtpout.prod.us-west-2.prod.farcaster.email.amazon.dev) ([10.43.8.6]) by smtp-border-fw-52005.iad7.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Feb 2024 07:24:53 +0000 Received: from EX19MTAEUB002.ant.amazon.com [10.0.43.254:9420] by smtpin.naws.eu-west-1.prod.farcaster.email.amazon.dev [10.0.14.233:2525] with esmtp (Farcaster) id fba90ec5-3aa3-4313-b7ad-83557396f1db; Thu, 1 Feb 2024 07:24:52 +0000 (UTC) X-Farcaster-Flow-ID: fba90ec5-3aa3-4313-b7ad-83557396f1db Received: from EX19D028EUC004.ant.amazon.com (10.252.61.145) by EX19MTAEUB002.ant.amazon.com (10.252.51.59) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.40; Thu, 1 Feb 2024 07:24:51 +0000 Received: from EX19D037EUC001.ant.amazon.com (10.252.61.220) by EX19D028EUC004.ant.amazon.com (10.252.61.145) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.40; Thu, 1 Feb 2024 07:24:51 +0000 Received: from EX19D037EUC001.ant.amazon.com ([fe80::d0f1:b6b6:e660:ae67]) by EX19D037EUC001.ant.amazon.com ([fe80::d0f1:b6b6:e660:ae67%3]) with mapi id 15.02.1118.040; Thu, 1 Feb 2024 07:24:51 +0000 From: "Bernstein, Amit" To: "tglx@linutronix.de" , "richardcochran@gmail.com" CC: "kuba@kernel.org" , "netdev@vger.kernel.org" , "Dagan, Noam" , "Arinzon, David" , "Agroskin, Shay" Subject: Add PHC support with error bound value for ENA driver Thread-Topic: Add PHC support with error bound value for ENA driver Thread-Index: AdpU32temyuKTDgWRNqtQlnNzjS4cQ== Date: Thu, 1 Feb 2024 07:24:51 +0000 Message-ID: <8803342f01f54ca38296cedafea10bde@amazon.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Hi Thomas, Richard and all, In one of the upcoming releases, we're planning to add PHC support to the E= NA driver (/drivers/net/ethernet/amazon/ena/) To provide the best experience for service customers, the ENA driver will e= xpose an error_bound parameter (expressed in nanoseconds),=20 which will represent the maximal clock error on each given PHC timestamp. The error bound is calculated by the device, taking into account the accur= acy and delays of all the device's PHC components. Based on our search, there is no similar functionality in other drivers, me= aning there is no user interface to expose it. We're currently exploring the best method of exposing this capability to th= e user. Our debate is between: - Extending the gettimex64 API in ptp_clock_info - Introducing a new devlink entry - Updating the time-related ethtool option (-T flag). As our device sends each PHC timestamp with an error_bound value together, = gettimex64 is the reasonable option for us and our recommended solution. We would like to ask for your recommendation. We have already consulted with Jakub, who recommended that we consult with = all of you. For more information, you may visit: https://aws.amazon.com/blogs/compute/i= ts-about-time-microsecond-accurate-clocks-on-amazon-ec2-instances/ Thanks, Amit