From patchwork Thu Jul 20 11:05:39 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Bruce Richardson X-Patchwork-Id: 129667 X-Patchwork-Delegate: thomas@monjalon.net Return-Path: X-Original-To: patchwork@inbox.dpdk.org Delivered-To: patchwork@inbox.dpdk.org Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 3596E42EC5; Thu, 20 Jul 2023 13:05:54 +0200 (CEST) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 1671C40F17; Thu, 20 Jul 2023 13:05:50 +0200 (CEST) Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by mails.dpdk.org (Postfix) with ESMTP id ADAB940DF5 for ; Thu, 20 Jul 2023 13:05:47 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1689851147; x=1721387147; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=sI1ALSjU26ydmkWNTxFjCcL6lvY/iXK9r4vmYGA0vBQ=; b=LINd6GKmLE9Rvx3v9Q6GUXYCPDTBSO0NB9Qs+/+LlpNCKnYleNS9oWgA ANJOi1Ew0ku2UhXFjV54/Hrcx6+hA88wBQWzaBFo8VZ2/dPlPtEl3ik1n KcCWEDKRUAPGRTnKfxco2m2jjddKfv5kxUtUJns/saTKIgxwfAEGexMn2 2s8thMaKklkXtRYi2VCQRv4pQ9L1pZCJ8l1kvl/TZB6lmBvSvzPe5hm2M 4fObawnJKLomKD2lvA0LS9g8x2CaO6tp2R6vqnyU+PAaMpiuduOgigqzf Jjadrb5awPxXhXZvIntAXztK/UkgTCcWx3Rm2bb4B+yeWmf34X4mF8IyQ g==; X-IronPort-AV: E=McAfee;i="6600,9927,10776"; a="366731410" X-IronPort-AV: E=Sophos;i="6.01,218,1684825200"; d="scan'208";a="366731410" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Jul 2023 04:05:46 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10776"; a="674650218" X-IronPort-AV: E=Sophos;i="6.01,218,1684825200"; d="scan'208";a="674650218" Received: from silpixa00401385.ir.intel.com ([10.237.214.156]) by orsmga003.jf.intel.com with ESMTP; 20 Jul 2023 04:05:45 -0700 From: Bruce Richardson To: dev@dpdk.org Cc: Bruce Richardson , Chengwen Feng , David Marchand Subject: [PATCH v4 1/2] doc/contributing: provide coding details for dynamic logging Date: Thu, 20 Jul 2023 12:05:39 +0100 Message-Id: <20230720110540.231342-2-bruce.richardson@intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230720110540.231342-1-bruce.richardson@intel.com> References: <20230613143355.77914-1-bruce.richardson@intel.com> <20230720110540.231342-1-bruce.richardson@intel.com> MIME-Version: 1.0 X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org While the section on dynamic logging in the contributors guide covered the details of the logging naming scheme, it failed to cover exactly how the component developer, i.e. the contributor, could actually use dynamic logging in their component. Fix this by splitting the details of the naming scheme into a separate subsection, and adding to the introduction on logging, a recommendation (and example) to use RTE_LOG_REGISTER_DEFAULT. Similarly, when discussing specialization, include a reference to the RTE_LOG_REGISTER_SUFFIX macro. Signed-off-by: Bruce Richardson Acked-by: Chengwen Feng Reviewed-by: David Marchand --- doc/guides/contributing/coding_style.rst | 22 ++++++++++++++++++++++ lib/cfgfile/rte_cfgfile.c | 2 ++ 2 files changed, 24 insertions(+) diff --git a/doc/guides/contributing/coding_style.rst b/doc/guides/contributing/coding_style.rst index 00d6270624..383942a601 100644 --- a/doc/guides/contributing/coding_style.rst +++ b/doc/guides/contributing/coding_style.rst @@ -803,6 +803,26 @@ logging of a particular topic, the ``--log-level`` parameter can be provided to EAL, which will change the log level. DPDK code can register topics, which allows the user to adjust the log verbosity for that specific topic. +To register a library or driver for dynamic logging, using the standardized naming scheme described below, +use ``RTE_LOG_REGISTER_DEFAULT`` macro to define a log-type variable inside your component's main C file. +Thereafter, it is usual to define a macro or macros inside your component to make logging more convenient. + +For example, the ``rte_cfgfile`` library defines: + +.. literalinclude:: ../../../lib/cfgfile/rte_cfgfile.c + :language: c + :start-after: Setting up dynamic logging 8< + :end-before: >8 End of setting up dynamic logging + +.. note:: + + The statically-defined log types defined in ``rte_log.h`` are for legacy components, + and they will likely be removed in a future release. + Do not add new entries to this file. + +Dynamic Logging Naming Scheme +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + In general, the naming scheme is as follows: ``type.section.name`` * Type is the type of component, where ``lib``, ``pmd``, ``bus`` and ``user`` @@ -837,6 +857,8 @@ A specialization looks like this: * Initialization output: ``type.section.name.init`` * PF/VF mailbox output: ``type.section.name.mbox`` +These specializations are created using the ``RTE_LOG_REGISTER_SUFFIX`` macro. + A real world example is the i40e poll mode driver which exposes two specializations, one for initialization ``pmd.net.i40e.init`` and the other for the remaining driver logs ``pmd.net.i40e.driver``. diff --git a/lib/cfgfile/rte_cfgfile.c b/lib/cfgfile/rte_cfgfile.c index 9fa7d010ef..eefba6e408 100644 --- a/lib/cfgfile/rte_cfgfile.c +++ b/lib/cfgfile/rte_cfgfile.c @@ -27,11 +27,13 @@ struct rte_cfgfile { struct rte_cfgfile_section *sections; }; +/* Setting up dynamic logging 8< */ RTE_LOG_REGISTER_DEFAULT(cfgfile_logtype, INFO); #define CFG_LOG(level, fmt, args...) \ rte_log(RTE_LOG_ ## level, cfgfile_logtype, "%s(): " fmt "\n", \ __func__, ## args) +/* >8 End of setting up dynamic logging */ /** when we resize a file structure, how many extra entries * for new sections do we add in */ From patchwork Thu Jul 20 11:05:40 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Bruce Richardson X-Patchwork-Id: 129668 X-Patchwork-Delegate: thomas@monjalon.net Return-Path: X-Original-To: patchwork@inbox.dpdk.org Delivered-To: patchwork@inbox.dpdk.org Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id A341E42EC5; Thu, 20 Jul 2023 13:05:59 +0200 (CEST) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 5B50942BAC; Thu, 20 Jul 2023 13:05:51 +0200 (CEST) Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by mails.dpdk.org (Postfix) with ESMTP id 7AA5940F17 for ; Thu, 20 Jul 2023 13:05:49 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1689851149; x=1721387149; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=ZXtPSSyku++JOWN9I5+Em8FSwBKbxPychmKFDS5wkEU=; b=JbTOB4k2Xmz0FOSBfhE2OuVTWclZ5WATF3Z1BOXrW/HZwDppIXtbpGQM 9UWZNQVWiEF2H8gI4gbtNGBV70bhKMFN0u30xJIi6+g1S/qHtAU6fUPcq SJ/y2rx8dc1o027srlLea26pFLLSl4mvzZySJNjC4PdcbdFVd5RGo/6V2 q6n3rM7zRavb+CWZC2QXYiDuuO51StyaPwDzBkwgyezan0tcmybrNawqA 3ZE2AnbPhhYVS3kcn67sTax+YWkbybEj+Y1liC94sR4ZrFafQBdJDAEXR v50K+8Luxl02HoU5TkX69ngDQcgn7pDGWlZ5DX9ZIjl8U1axZkA+xwlbk A==; X-IronPort-AV: E=McAfee;i="6600,9927,10776"; a="366731420" X-IronPort-AV: E=Sophos;i="6.01,218,1684825200"; d="scan'208";a="366731420" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 20 Jul 2023 04:05:48 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10776"; a="674650227" X-IronPort-AV: E=Sophos;i="6.01,218,1684825200"; d="scan'208";a="674650227" Received: from silpixa00401385.ir.intel.com ([10.237.214.156]) by orsmga003.jf.intel.com with ESMTP; 20 Jul 2023 04:05:46 -0700 From: Bruce Richardson To: dev@dpdk.org Cc: Bruce Richardson , =?utf-8?q?Morten_Br=C3=B8?= =?utf-8?q?rup?= , Jerin Jacob , David Marchand Subject: [PATCH v4 2/2] doc/contributing: guidelines for logging, tracing and telemetry Date: Thu, 20 Jul 2023 12:05:40 +0100 Message-Id: <20230720110540.231342-3-bruce.richardson@intel.com> X-Mailer: git-send-email 2.39.2 In-Reply-To: <20230720110540.231342-1-bruce.richardson@intel.com> References: <20230613143355.77914-1-bruce.richardson@intel.com> <20230720110540.231342-1-bruce.richardson@intel.com> MIME-Version: 1.0 X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org As discussed by DPDK technical board [1], our contributor guide should include some details as to when to use logging vs tracing vs telemetry to provide the end user with information about the running process and the DPDK libraries it uses. [1] https://mails.dpdk.org/archives/dev/2023-March/265204.html Signed-off-by: Bruce Richardson Acked-by: Morten Brørup Acked-by: Jerin Jacob Reviewed-by: David Marchand --- doc/guides/contributing/coding_style.rst | 2 + doc/guides/contributing/design.rst | 49 ++++++++++++++++++++++++ doc/guides/prog_guide/telemetry_lib.rst | 2 + doc/guides/prog_guide/trace_lib.rst | 2 + 4 files changed, 55 insertions(+) diff --git a/doc/guides/contributing/coding_style.rst b/doc/guides/contributing/coding_style.rst index 383942a601..37e2cc5efb 100644 --- a/doc/guides/contributing/coding_style.rst +++ b/doc/guides/contributing/coding_style.rst @@ -794,6 +794,8 @@ Control Statements /* NOTREACHED */ } +.. _dynamic_logging: + Dynamic Logging --------------- diff --git a/doc/guides/contributing/design.rst b/doc/guides/contributing/design.rst index d24a7ff6a0..5a4c4b7ed1 100644 --- a/doc/guides/contributing/design.rst +++ b/doc/guides/contributing/design.rst @@ -4,6 +4,7 @@ Design ====== + Environment or Architecture-specific Sources -------------------------------------------- @@ -68,6 +69,54 @@ Adding a new static field or flag must be an exception matching many criteria like (non exhaustive): wide usage, performance, size. +Runtime Information - Logging, Tracing and Telemetry +------------------------------------------------------- + +It is often desirable to provide information to the end-user as to what is happening to the application at runtime. +DPDK provides a number of built-in mechanisms to provide this introspection: + +* :ref:`Logging` +* :ref:`Tracing` +* :ref:`Telemetry` + +Each of these has its own strengths and suitabilities for use within DPDK components. + +Below are some guidelines for when each should be used: + +* For reporting error conditions, or other abnormal runtime issues, *logging* should be used. + Depending on the severity of the issue, the appropriate log level, for example, + ``ERROR``, ``WARNING`` or ``NOTICE``, should be used. + +.. note:: + + Drivers of all classes, including both bus and device drivers, + should not output any log information if the hardware they support is not present. + This is to avoid any changes in output for existing users when a new driver is added to DPDK. + +* For component initialization, or other cases where a path through the code is only likely to be taken once, + either *logging* at ``DEBUG`` level or *tracing* may be used, or potentially both. + In the latter case, tracing can provide basic information as to the code path taken, + with debug-level logging providing additional details on internal state, + not possible to emit via tracing. + +* For a component's data-path, where a path is to be taken multiple times within a short timeframe, + *tracing* should be used. + Since DPDK tracing uses `Common Trace Format `_ for its tracing logs, + post-analysis can be done using a range of external tools. + +* For numerical or statistical data generated by a component, for example, per-packet statistics, + *telemetry* should be used. + +* For any data where the data may need to be gathered at any point in the execution to help assess the state of the application component, + for example, core configuration, device information, *telemetry* should be used. + Telemetry callbacks should not modify any program state, but be "read-only". + +Many libraries also include a ``rte__dump()`` function as part of their API, +writing verbose internal details to a given file-handle. +New libraries are encouraged to provide such functions where it makes sense to do so, +as they provide an additional application-controlled mechanism to get details of the internals of a DPDK component. + + Library Statistics ------------------ diff --git a/doc/guides/prog_guide/telemetry_lib.rst b/doc/guides/prog_guide/telemetry_lib.rst index 32f525a67f..71f8bd735e 100644 --- a/doc/guides/prog_guide/telemetry_lib.rst +++ b/doc/guides/prog_guide/telemetry_lib.rst @@ -1,6 +1,8 @@ .. SPDX-License-Identifier: BSD-3-Clause Copyright(c) 2020 Intel Corporation. +.. _telemetry_library: + Telemetry Library ================= diff --git a/doc/guides/prog_guide/trace_lib.rst b/doc/guides/prog_guide/trace_lib.rst index e5718feddc..a3b8a7c2eb 100644 --- a/doc/guides/prog_guide/trace_lib.rst +++ b/doc/guides/prog_guide/trace_lib.rst @@ -1,6 +1,8 @@ .. SPDX-License-Identifier: BSD-3-Clause Copyright(C) 2020 Marvell International Ltd. +.. _trace_library: + Trace Library =============