From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by dpdk.space (Postfix) with ESMTP id 298DCA0AC5 for ; Thu, 2 May 2019 14:11:45 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 068C54CAB; Thu, 2 May 2019 14:11:44 +0200 (CEST) Received: from smtp-4.sys.kth.se (smtp-4.sys.kth.se [130.237.48.193]) by dpdk.org (Postfix) with ESMTP id 48ABE4C95 for ; Thu, 2 May 2019 14:11:42 +0200 (CEST) Received: from smtp-4.sys.kth.se (localhost.localdomain [127.0.0.1]) by smtp-4.sys.kth.se (Postfix) with ESMTP id EBF4767EC; Thu, 2 May 2019 14:11:41 +0200 (CEST) X-Virus-Scanned: by amavisd-new at kth.se Received: from smtp-4.sys.kth.se ([127.0.0.1]) by smtp-4.sys.kth.se (smtp-4.sys.kth.se [127.0.0.1]) (amavisd-new, port 10024) with LMTP id 10JAU8A3snCC; Thu, 2 May 2019 14:11:41 +0200 (CEST) X-KTH-Auth: barbette [192.16.125.171] DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kth.se; s=default; t=1556799101; bh=hrbvMB6sy2GhFyEJLZG9mmBjBSA81drNtJzcCSORSbM=; h=From:To:Cc:Subject:Date; b=eC52pVt0hhjI4HpHm67SphfLCAXThk/EejK7j4e0PmY8Jzf2sm7QsrAmQRzMdfuKR l4d6a8oD0nztoMmcnbSeymz7V7iXCdyb7m74QmIP1Y0i4IDRNAxisLRhv7yKCgDzQx k44cBq6xWrFP7gRGpOfBd1dqJ8+KakExRUCZksDs= X-KTH-mail-from: barbette@kth.se Received: from nslrack11.ssvl.kth.se (nslrack11.ssvl.kth.se [192.16.125.171]) by smtp-4.sys.kth.se (Postfix) with ESMTPSA id CBBD56792; Thu, 2 May 2019 14:11:39 +0200 (CEST) From: Tom Barbette To: dev@dpdk.org Cc: bruce.richardson@intel.com, john.mcnamara@intel.com, Thomas Monjalon , Ferruh Yigit , Andrew Rybchenko , Shahaf Shuler , Yongseok Koh , olivier.matz@6wind.com, Tom Barbette Date: Thu, 2 May 2019 14:11:32 +0200 Message-Id: <20190502121135.18775-1-barbette@kth.se> X-Mailer: git-send-email 2.17.1 Subject: [dpdk-dev] [PATCH v4 0/3] Add rte_eth_read_clock API X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org Sender: "dev" Content-Type: text/plain; charset="UTF-8" Message-ID: <20190502121132.XPTZF96HsnhcC6Z4-KtRmi4XfzNDp5diywbUF-0YPJE@z> Some NICs allow to timestamp packets, but do not support the full PTP synchronization process. Hence, the value set in the mbuf timestamp field is only the raw value of an internal clock. To make sense of this value, one at least needs to be able to query the current hardware clock value. This patch series adds a new API to do so, rte_eth_read_clock. As with the TSC, from there a frequency can be derieved by querying multiple time the current value of the internal clock with some known delay between the queries (example provided in the API doc). This patch series adds support of read_clock for MLX5. An example app is provided in the rxtx_callback application. It has been updated to display, on top of the software latency in cycles, the total latency since the packet was received in hardware. The API is used to compute a delta in the Tx callback. The raw amount of ticks is converted to cycles using a variation of the technique describe above. Aside from offloading timestamping, which relieve the software from a few operations, this allows to get much more precision when studying the source of the latency in a system. Eg. in our 100G, CX5 setup the rxtx callback application shows SW latency is around 74 cycles (TSC is 3.2Ghz), but the latency including NIC processing, PCIe, and queuing is around 196 cycles. One may think at first this API is overlapping with te_eth_timesync_read_time. rte_eth_timesync_read_time is clearly identified as part of a set of functions to use PTP synchronization. The device raw clock is not "sync" in any way. More importantly, the returned value is not a timeval, but an amount of ticks. We could have a cast-based solution, but on top of being an ugly solution, some people seeing the timeval type of rte_eth_timesync_read_time could use it blindly. Change in v2: - Rebase on current master Change in v3: - Address comments from Ferruh Yigit Changes in v4: - Address comments from Keith Wiles and Andrew Rybchenko - Use "clock" as argunment name everywhere. - Expand the API description to make clear that read_clock gives an amount in ticks, and that it has no unit. Tom Barbette (3): rte_ethdev: Add API function to read dev clock mlx5: Implement support for read_clock rxtx_callbacks: Add support for HW timestamp doc/guides/nics/features.rst | 1 + doc/guides/sample_app_ug/rxtx_callbacks.rst | 9 ++- drivers/net/mlx5/mlx5.c | 1 + drivers/net/mlx5/mlx5.h | 1 + drivers/net/mlx5/mlx5_ethdev.c | 30 +++++++ drivers/net/mlx5/mlx5_glue.c | 8 ++ drivers/net/mlx5/mlx5_glue.h | 2 + examples/rxtx_callbacks/Makefile | 3 + examples/rxtx_callbacks/main.c | 87 ++++++++++++++++++++- examples/rxtx_callbacks/meson.build | 3 + lib/librte_ethdev/rte_ethdev.c | 12 +++ lib/librte_ethdev/rte_ethdev.h | 47 +++++++++++ lib/librte_ethdev/rte_ethdev_core.h | 6 ++ lib/librte_ethdev/rte_ethdev_version.map | 1 + lib/librte_mbuf/rte_mbuf.h | 2 + 15 files changed, 208 insertions(+), 5 deletions(-) -- 2.17.1