From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp-fw-2101.amazon.com (smtp-fw-2101.amazon.com [72.21.196.25]) (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 748527E110 for ; Mon, 26 May 2025 06:12:29 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=72.21.196.25 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748239951; cv=none; b=taCN0mLGTmxDuzcr+gs6XUAzN0WvguZZkrXDeJ88nA/uixmQrPl89spC0GgQcy2iKuxXO8qLh+8ms7AK6l/9WBDiY8Wn+xdcji8jD5dLD39laxFiReiStob1umQeQw6g1xaVJOoVOne7Oi0xFV1bgHe33y6W9QdRAztvT58j8jk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1748239951; c=relaxed/simple; bh=vKiTYOcvwoQmM0ImQU64EU7uXY0aj4ywj0be8wiZjD4=; h=From:To:CC:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=pawEH6TNR3Jum3lfalB+6vaWNRSuRRc6W7AT9WI0kKyX9yGxb+ip5cBI6T9KBSfsC+layxwwlnblVkYr/HVYLunue3eCQnyyhYRWDUUyK0/p6A715VG4SugbecWdoJ9nq+pteYQC9B7PH1GDQioaHY8aXWm7Z4lkHYrXA2FwIXM= 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 (2048-bit key) header.d=amazon.com header.i=@amazon.com header.b=kyqGcBjZ; arc=none smtp.client-ip=72.21.196.25 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 (2048-bit key) header.d=amazon.com header.i=@amazon.com header.b="kyqGcBjZ" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=amazon.com; i=@amazon.com; q=dns/txt; s=amazoncorp2; t=1748239949; x=1779775949; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=mh3kzTbRrFl/E7avOcV9qzXi75piTAx505VHtT6pCAk=; b=kyqGcBjZtLIf3SmPMEWGUyhrnDOFl80YNu7Z22xNeDRWJsA3N9p4AMgx JJpBuIw5etXpuQJLuncYtGjY9C5+xxG9OU6pHSAxSxqDlV+0fb6AfGD2m 6UAriRrEa/JccebmqxBSbI1IT4YV+eLHskQepyLo6ROrfM2AjVEaNOUys ZQrjzrfyyzrN/fioNGlyI0tAHSuUgBnIT+KWk4+96I7O4LcCSbH6SghZr k8V8/4kivO55/zwkkAk2+6wRrako1h92egC9lzcfD6SIypEda3UgNQwpF mfkVcgJF0vfEDfn72Kt57gykQ/KjtiS55qHFXbUHO1l5tgdQ7AHZr28sT g==; X-IronPort-AV: E=Sophos;i="6.15,315,1739836800"; d="scan'208";a="496118626" Received: from iad12-co-svc-p1-lb1-vlan3.amazon.com (HELO smtpout.prod.us-east-1.prod.farcaster.email.amazon.dev) ([10.43.8.6]) by smtp-border-fw-2101.iad2.amazon.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 May 2025 06:12:28 +0000 Received: from EX19MTAEUC002.ant.amazon.com [10.0.43.254:56961] by smtpin.naws.eu-west-1.prod.farcaster.email.amazon.dev [10.0.35.44:2525] with esmtp (Farcaster) id b0dbafe9-81c3-4252-b84a-25860cc5f158; Mon, 26 May 2025 06:12:27 +0000 (UTC) X-Farcaster-Flow-ID: b0dbafe9-81c3-4252-b84a-25860cc5f158 Received: from EX19D005EUA002.ant.amazon.com (10.252.50.11) by EX19MTAEUC002.ant.amazon.com (10.252.51.245) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1544.14; Mon, 26 May 2025 06:12:26 +0000 Received: from HFA15-G9FV5D3.amazon.com (10.85.143.177) by EX19D005EUA002.ant.amazon.com (10.252.50.11) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA) id 15.2.1544.14; Mon, 26 May 2025 06:12:15 +0000 From: David Arinzon To: David Miller , Jakub Kicinski , CC: David Arinzon , Eric Dumazet , Paolo Abeni , Simon Horman , "Richard Cochran" , "Woodhouse, David" , "Machulsky, Zorik" , "Matushevsky, Alexander" , Saeed Bshara , "Wilson, Matt" , "Liguori, Anthony" , "Bshara, Nafea" , "Schmeilin, Evgeny" , "Belgazal, Netanel" , "Saidi, Ali" , "Herrenschmidt, Benjamin" , "Kiyanovski, Arthur" , "Dagan, Noam" , "Bernstein, Amit" , "Agroskin, Shay" , "Ostrovsky, Evgeny" , "Tabachnik, Ofir" , "Machnikowski, Maciek" , Rahul Rameshbabu , Gal Pressman , Vadim Fedorenko , Andrew Lunn , Leon Romanovsky , Jiri Pirko Subject: [PATCH v11 net-next 8/8] net: ena: Add PHC documentation Date: Mon, 26 May 2025 09:09:18 +0300 Message-ID: <20250526060919.214-9-darinzon@amazon.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20250526060919.214-1-darinzon@amazon.com> References: <20250526060919.214-1-darinzon@amazon.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain X-ClientProxiedBy: EX19D033UWA003.ant.amazon.com (10.13.139.42) To EX19D005EUA002.ant.amazon.com (10.252.50.11) Provide the relevant information and guidelines about the feature support in the ENA driver. Signed-off-by: Amit Bernstein Signed-off-by: David Arinzon --- .../device_drivers/ethernet/amazon/ena.rst | 103 ++++++++++++++++++ 1 file changed, 103 insertions(+) diff --git a/Documentation/networking/device_drivers/ethernet/amazon/ena.rst b/Documentation/networking/device_drivers/ethernet/amazon/ena.rst index 347aec34..6892e3f1 100644 --- a/Documentation/networking/device_drivers/ethernet/amazon/ena.rst +++ b/Documentation/networking/device_drivers/ethernet/amazon/ena.rst @@ -224,6 +224,109 @@ descriptor it was received on would be recycled. When a packet smaller than RX copybreak bytes is received, it is copied into a new memory buffer and the RX descriptor is returned to HW. +.. _`PHC`: + +PTP Hardware Clock (PHC) +======================== +.. _`ptp-userspace-api`: https://docs.kernel.org/driver-api/ptp.html#ptp-hardware-clock-user-space-api +.. _`testptp`: https://elixir.bootlin.com/linux/latest/source/tools/testing/selftests/ptp/testptp.c + +ENA Linux driver supports PTP hardware clock providing timestamp reference to achieve nanosecond resolution. + +**PHC support** + +PHC depends on the PTP module, which needs to be either loaded as a module or compiled into the kernel. + +Verify if the PTP module is present: + +.. code-block:: shell + + grep -w '^CONFIG_PTP_1588_CLOCK=[ym]' /boot/config-`uname -r` + +- If no output is provided, the ENA driver cannot be loaded with PHC support. + +- ``CONFIG_PTP_1588_CLOCK=y``: the PTP module is already compiled and loaded inside the kernel binary file. + +- ``CONFIG_PTP_1588_CLOCK=m``: the PTP module needs to be loaded prior to loading the ENA driver: + +Load PTP module: + +.. code-block:: shell + + sudo modprobe ptp + +**PHC activation** + +The feature is turned off by default, in order to turn the feature on, the ENA driver +can be loaded in the following way: + +- devlink: + +.. code-block:: shell + + sudo devlink dev param set pci/ name enable_phc value true cmode driverinit + sudo devlink dev reload pci/ + # for example: + sudo devlink dev param set pci/0000:00:06.0 name enable_phc value true cmode driverinit + sudo devlink dev reload pci/0000:00:06.0 + +All available PTP clock sources can be tracked here: + +.. code-block:: shell + + ls /sys/class/ptp + +PHC support and capabilities can be verified using ethtool: + +.. code-block:: shell + + ethtool -T + +**PHC timestamp** + +To retrieve PHC timestamp, use `ptp-userspace-api`_, usage example using `testptp`_: + +.. code-block:: shell + + testptp -d /dev/ptp$(ethtool -T | awk '/PTP Hardware Clock:/ {print $NF}') -k 1 + +PHC get time requests should be within reasonable bounds, +avoid excessive utilization to ensure optimal performance and efficiency. +The ENA device restricts the frequency of PHC get time requests to a maximum +of 125 requests per second. If this limit is surpassed, the get time request +will fail, leading to an increment in the phc_err_ts statistic. + +**PHC statistics** + +PHC can be monitored using debugfs (if mounted): + +.. code-block:: shell + + sudo cat /sys/kernel/debug//phc_stats + + # for example: + sudo cat /sys/kernel/debug/0000:00:06.0/phc_stats + +PHC errors must remain below 1% of all PHC requests to maintain the desired level of accuracy and reliability + +================= ====================================================== +**phc_cnt** | Number of successful retrieved timestamps (below expire timeout). +**phc_exp** | Number of expired retrieved timestamps (above expire timeout). +**phc_skp** | Number of skipped get time attempts (during block period). +**phc_err_dv** | Number of failed get time attempts due to device errors (entering into block state). +**phc_err_ts** | Number of failed get time attempts due to timestamp errors (entering into block state), + | This occurs if driver exceeded the request limit or device received an invalid timestamp. +================= ====================================================== + +PHC timeouts: + +================= ====================================================== +**expire** | Max time for a valid timestamp retrieval, passing this threshold will fail + | the get time request and block new requests until block timeout. +**block** | Blocking period starts once get time request expires or fails, + | all get time requests during block period will be skipped. +================= ====================================================== + Statistics ========== -- 2.47.1