From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id 583F7A00C2; Wed, 22 Apr 2020 12:55:39 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 1AC861D563; Wed, 22 Apr 2020 12:55:38 +0200 (CEST) Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by dpdk.org (Postfix) with ESMTP id 148441D55B for ; Wed, 22 Apr 2020 12:55:35 +0200 (CEST) IronPort-SDR: /VSQsZpVBWtho0qbe45AWxzFfbi3UT1V8F+PYcUTUlQVP2sicz89yCiRuGkvToXPR2wi4LxWEX 3cKsN60g6zZQ== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Apr 2020 03:55:35 -0700 IronPort-SDR: 2Hnb8iR0z9pgylKdyXN19PE8RREIbi0a9Il2GMZ5BDcb2ivNiCYe1j7mr/C637kHYIM1qr+YIe XqosRiG2SW8A== X-IronPort-AV: E=Sophos;i="5.72,414,1580803200"; d="scan'208";a="456463704" Received: from bricha3-mobl.ger.corp.intel.com ([10.214.196.230]) by fmsmga005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-SHA; 22 Apr 2020 03:55:24 -0700 Date: Wed, 22 Apr 2020 11:55:19 +0100 From: Bruce Richardson To: Lukasz Wojciechowski Cc: Thomas Monjalon , "Ananyev, Konstantin" , "Dumitrescu, Cristian" , Igor Russkikh , Pavel Belous , "Lu, Wenzhuo" , Marcin Wojtas , Michal Krawczyk , Guy Tzalik , Evgeny Schemeilin , Igor Chauskin , John Daley , Hyong Youb Kim , "Zhang, Qi Z" , "Wang, Xiao W" , Ziyang Xuan , Xiaoyun Wang , Guoyang Zhou , "Wei Hu (Xavier)" , "Min Hu (Connor)" , Yisen Zhuang , "Xing, Beilei" , "Wu, Jingjing" , "Yang, Qiming" , Rasesh Mody , Shahed Shaikh , "Singh, Jasvinder" , Maxime Coquelin , "Wang, Zhihong" , "Ye, Xiaolong" , Yong Wang , "Yigit, Ferruh" , Andrew Rybchenko , Olivier Matz , "dev@dpdk.org" Message-ID: <20200422105519.GB1402@bricha3-MOBL.ger.corp.intel.com> References: <20200417215739.23180-1-l.wojciechow@partner.samsung.com> <552291b0-32c1-d8db-034e-ecc599b4c940@partner.samsung.com> <1868765.PIDvDuAF1L@thomas> <237f3d8b-4040-15a2-a6c5-979aae9df8f2@partner.samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <237f3d8b-4040-15a2-a6c5-979aae9df8f2@partner.samsung.com> Subject: Re: [dpdk-dev] [PATCH v1 03/17] ethdev: replace library debug flag with global one 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" On Wed, Apr 22, 2020 at 12:41:49PM +0200, Lukasz Wojciechowski wrote: > > W dniu 21.04.2020 o 23:38, Thomas Monjalon pisze: > > 21/04/2020 22:58, Lukasz Wojciechowski: > >> W dniu 21.04.2020 o 02:32, Ananyev, Konstantin pisze: > >>>>>>>>>>> I am agree with Cristian concern here: that patch removes ability to > >>>>>>>>>>> enable/disable debug on particular library/PMD. If the purpose is to > >>>>>>>>>>> minimize number of config compile options, I wonder can't it be done > >>>>>>>>>>> in a slightly different way: 1. introduce gloabal RTE_DEBUG 2. keep > >>>>>>>>>>> actual .[c,h] files intact 3. In actual librte_xxx/meson.build file > >>>>>>>>>>> check if RTE_DEBUG is enabled, If yes, then enable particular debug > >>>>>>>>>>> flag for these libs. Something like: If dpdk_conf.get('RTE_DEBUG') == > >>>>>>>>>>> true dpdk_conf.set('RTE_LIBRTE_XXX_DEBUG ', 1) > >>>>>>>>>>> > >>>>>>>>>>> defines that are used by multiple libs, probably can be set in upper > >>>>>>>>>>> layer meson.build. > >>>>>>>>>>> > >>>>>>>>>>> That way will have global 'debug' flag, but users will still have an > >>>>>>>>>>> ability to enable/disable debug flags on a per lib basis via > >>>>>>>>>>> CFLAGS="-D..." > >>>>>>>>>>> > >>>>>>>>>>> Konstantin > >>>>>>>>>>> > >>>>>>>>>> That seems a reasonable idea to me. > >>>>>>>>>> > >>>>>>>>>> However, in this case, we don't need the RTE_DEBUG flag at all, we can > >>>>>>>>>> either: > >>>>>>>>>> > >>>>>>>>>> * allow each component meson.build file define its own flags after > >>>>>>>>>> checking get_option('debug') * have lib/meson.build and > >>>>>>>>>> drivers/meson.build automatically define a specific define for each > >>>>>>>>>> library or driver to standardize the naming. [This would save anyone > >>>>>>>>>> working on it from having to lookup what the define was, since it's > >>>>>>>>>> always e.g. RTE_DEBUG_ + library-base-name, e.g. RTE_DEBUG_LPM, > >>>>>>>>>> RTE_DEBUG_SCHED etc] > >>>>>>>>>> > >>>>>>>>>> Theoretically we can also do both, have the standard ones defined and > >>>>>>>>>> then allow a component to provide extra flags itself if so desired. > >>>>>>>>>> > >>>>>>>>>> /Bruce > >>>>>>>>> OK, so let's summarize how the patches should be redo: * usage of global > >>>>>>>>> "debug" flag for meson build stays * we standardize names of debug flags > >>>>>>>>> in the components to RTE_DEBUG_ + components name * debug flag enables al > >>>>>>>>> the RTE_DEBUG_... flags > >>>>>>>>> > >>>>>>>>> This allow to easily use both: * the debug flag - to enable all debugs * > >>>>>>>>> or define manually RTE_DEBUG+component name, just for debug from a single > >>>>>>>>> component > >>>>>>>>> > >>>>>>>>> I like Bruce's idea of adding it to the lib/meson.build and > >>>>>>>>> drivers/meson.build. This way they will be added to dpdk_conf meson > >>>>>>>>> object and written then later to rte_build_config.h before compilation > >>>>>>>>> stage. All the other modules will be able to use these flags. > >>>>>>>>> > >>>>>>>> Sounds good to me (obviously!), but I'd like other feedback to ensure > >>>>>>>> others are ok with this before you spend too much effort implementing it. > >>>>>>>> > >>>>>>>> For the drivers, the flag probably needs to include the category as well as > >>>>>>>> the name, e.g. RTE_DEBUG_NET_IXGBE, RTE_DEBUG_RAW_IOAT, to avoid possible > >>>>>>>> name confusion. Those flags can then be checked inside individual > >>>>>>>> meson.build files to enable other debug flags if necessary e.g. in ixgbe, > >>>>>>>> you could theoretically do: > >>>>>>>> > >>>>>>>> if dpdk_conf.has('RTE_DEBUG_NET_IXGBE') > >>>>>>>> cflags += '-DRTE_LIBRTE_IXGBE_DEBUG_RX' > >>>>>>>> cflags += '-DRTE_LIBRTE_IXGBE_DEBUG_TX' > >>>>>>>> ... > >>>>>>>> endif > >>>>>>>> > >>>>>>>> to enable more fine-grained control if so desired, and to maintain > >>>>>>>> compatibility with existing defines, again if so desired. > >>>>>>> Nak the nak from Cristian. > >>>>>>> > >>>>>>> We don't need all these flags. > >>>>>>> If the user choose to compile DPDK for debug, every debug facilities > >>>>>>> should be enabled. Then at runtime it is possible to enable/disable > >>>>>>> the interesting logs. > >>>>>>> If you need to disable something which is not a log, > >>>>>>> you can align with the log level thanks to the function rte_log_can_log. > >>> For many libs these flags mean much more than just logging. > >>> Let say RTE_LIBRTE_ETHDEV_DEBUG changes behaviour of tx_prepare() for many > >>> drivers - extra validation performed. > >>> RTE_LIBRTE_MBUF_DEBUG makes __rte_mbuf_sanity_check() a call to real > >>> rte_mbuf_sanity_check() instead of just NOP. > >>> Which means performance would be greatly affected. > >>> RTE_LIBRTE_MEMPOOL_DEBUG changes format of the mempool object header > >>> and enforce extra checking, stats collection. > >>> etc. > >>> Probably that's ok for some cases to enable all that extra validation we have at once. > >>> But I suppose in many cases people just interested to enable debug on one > >>> (ok might be two/three) particular libraries, not the whole system. > >>> Right now there is such ability, we are going to remove it without > >>> providing adequate replacement. > >>> Approach with rte_log_can_log() seems workable, > >>> but right now these patches don't implement it. > >>> Konstantin > >>> > >>>>>>> Please let's stop complicating things for the contributors and the users. > >>>>>>> Note: I am strong on this position. > >>>>>>> > >>>>>> Note, this means that you need to ensure all debug printouts from libs and > >>>>>> drivers are using the RTE_LOG macros so can be runtime controlled. I think > >>>>>> that may be some distance from reality right now. > >>>>> Perfect! Let's expose those nasty logs which are not (yet) controllable. > >>>>> And next step is to block any patch in those drivers or libs, > >>>>> until it is fixed. Dynamic logging should have been complete for long. > >>>>> > >>>> I can live with that, I suppose. Do we have any idea of the magnitude of > >>>> the work required here? > >>>> > >>>>>> Even if we do want all debug enabled from one flag, I'm still not 100% > >>>>>> convinced that the existing debug flag is the way to do, since it only adds > >>>>>> debug info to binary without affecting code generation. > >>>>> OK, we want to keep this flag for gdb symbols only? > >>>>> And add a new flag for debugging facilities which hurt the runtime performance? > >>>>> > >>>> I think that would be wise, yes. We can call the option "rte_debug" or > >>>> something instead. > >>>> > >>>> /Bruce > >> OK, lets's summarize current opinions and requirements to make a > >> proposal for version2 of these patches, that I can implement if all agree: > >> > >> 1) The global debug flag is required to enable all the sanity checks and > >> validations that are normally not used due to performance reasons > > Yes > > > >> 2) The best option would be to have a single flag - not to introduce too > >> many build options > > Yes > > > >> 3) This option should be separated from meson "debug" option (used for > >> build with symbols) and can be called "rte_debug" > > Yes, it looks to be the consensus. > > > >> 4) The currently existing DEBUG macros should not be replaced with a > >> RTE_DEBUG macro. This would allow to still enable them using > >> CFLAGS="-D..." to test a single module (library, driver). > >> > >> 5) Currently existing options' names should be standardized to > >> RTE_DEBUG_{library/driver name}, so they can be automatically enabled > >> when rte_debug is set. Standardized names would allow easy usage in > >> other modules. > > I don't understand difference between 4) et 5). > > In current version of patches, I replaced all the DEBUG macros with > RTE_DEBUG. It would be much better to keep fine-grained debugs as they > are defined currently in dpdk. This is what I have on mind in 4) > > However the currently used debug macros have different naming > conventions: some use RTE_LIBRTE_{name}_DEBUG convention, other > RTE_{name}_DEBUG, some just {name}_DEBUG. > So in 5) I follow Bruce's proposal to standardize them to one form > RTE_DEBUG_{name}. However this will change the existing macros and > someone might not like it, so I ask for the opinion about it. > My thought is to standardize in the build and then leave it to module owners to either change their macros to use those standard ones as time goes on. > > >> Should they? Or should we leave the current debug macros? Please share > >> your opinions as I see both cons and pros of this idea. > > I am not sure we need to keep fine-grain debug flags per libs/drivers. > > In case RTE_DEBUG is enabled, which kind of debug processing > > (except logs) do we want to be able to disable? > > Is it possible to decide based on a call to rte_log_can_log()? > I think it's rather opposite way round. Sometimes we would like to > enable just some debug processing, e.g. when working on single lib or > driver. > If we will use rte_debug - every debug  processing would be enabled, we > won't disable anything, but without rte_debug we will still have the > possibility of enabling debugs on a single module. > > I believe it is possible to do it with rte_log_can_log, but changing > build time enabled options into runtime enabled options might affect > performance. It might make working on a single library or driver harder. > I think the idea is to use both. When RTE_DEBUG is enabled, then the rte_log_can_log() calls will be used to control the actual output. Without RTE_DEBUG, the whole block is skipped. #ifdef RTE_DEBUG if rte_log_can_log(...) { /* do debug stuff */ } #endif