From patchwork Mon Jul 27 15:51:04 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Slava Ovsiienko X-Patchwork-Id: 74859 X-Patchwork-Delegate: thomas@monjalon.net Return-Path: X-Original-To: patchwork@inbox.dpdk.org Delivered-To: patchwork@inbox.dpdk.org Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id D44F6A053D; Mon, 27 Jul 2020 17:51:08 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id A5C281BFE2; Mon, 27 Jul 2020 17:51:07 +0200 (CEST) Received: from mellanox.co.il (mail-il-dmz.mellanox.com [193.47.165.129]) by dpdk.org (Postfix) with ESMTP id 1BE321BFDD for ; Mon, 27 Jul 2020 17:51:06 +0200 (CEST) Received: from Internal Mail-Server by MTLPINE1 (envelope-from viacheslavo@mellanox.com) with SMTP; 27 Jul 2020 18:51:05 +0300 Received: from pegasus12.mtr.labs.mlnx (pegasus12.mtr.labs.mlnx [10.210.17.40]) by labmailer.mlnx (8.13.8/8.13.8) with ESMTP id 06RFp515022428; Mon, 27 Jul 2020 18:51:05 +0300 Received: from pegasus12.mtr.labs.mlnx (localhost [127.0.0.1]) by pegasus12.mtr.labs.mlnx (8.14.7/8.14.7) with ESMTP id 06RFp5V2012950; Mon, 27 Jul 2020 15:51:05 GMT Received: (from viacheslavo@localhost) by pegasus12.mtr.labs.mlnx (8.14.7/8.14.7/Submit) id 06RFp5IQ012949; Mon, 27 Jul 2020 15:51:05 GMT X-Authentication-Warning: pegasus12.mtr.labs.mlnx: viacheslavo set sender to viacheslavo@mellanox.com using -f From: Viacheslav Ovsiienko To: dev@dpdk.org Cc: matan@mellanox.com, rasland@mellanox.com, thomas@monjalon.net, ferruh.yigit@intel.com Date: Mon, 27 Jul 2020 15:51:04 +0000 Message-Id: <1595865064-12892-1-git-send-email-viacheslavo@mellanox.com> X-Mailer: git-send-email 1.8.3.1 Subject: [dpdk-dev] [PATCH v2] doc/mlx5: add timestamp upper limitation description 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" Add description about Tx scheduling timstamp upper limit. It timstamp exceed the value it is marked by PMD as being into "too-distant-future" and not scheduled at all (is being sent without any wait). Signed-off-by: Viacheslav Ovsiienko --- v1->v2: typo fix doc/guides/nics/mlx5.rst | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/doc/guides/nics/mlx5.rst b/doc/guides/nics/mlx5.rst index 90202c0..b9bd3db 100644 --- a/doc/guides/nics/mlx5.rst +++ b/doc/guides/nics/mlx5.rst @@ -253,6 +253,13 @@ Limitations reported via device xstats to assist applications to detect the time-related problems. + The timestamp upper "too-distant-future" limit at the moment of invoking + the tx_burst routine can be estimated as ``tx_pp`` devarog (in nanoseconds) + multiplied by 2^23. Please note, for the testpmd txonly testcase the limit + is deduced from the expression:: + + (n_tx_descriptors / burst_size + 1) * inter_burst_gap + There is no any packet reordering according timestamps is supposed, neither within packet burst, nor between packets, it is an entirely application responsibility to generate packets and its timestamps