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 63270A04DB; Fri, 16 Oct 2020 18:44:17 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 038892E1E; Fri, 16 Oct 2020 18:44:16 +0200 (CEST) Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by dpdk.org (Postfix) with ESMTP id 5E0AD1CF91 for ; Fri, 16 Oct 2020 17:57:08 +0200 (CEST) IronPort-SDR: Tgm2xTQVFB8Max2Ish6TU6JXeWcw7BX89aJpg9VGJwmPdVmSLBAbutui23XBswK7dAb6UV+83P Rh5iYDcTEd9w== X-IronPort-AV: E=McAfee;i="6000,8403,9776"; a="230822622" X-IronPort-AV: E=Sophos;i="5.77,383,1596524400"; d="scan'208";a="230822622" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 16 Oct 2020 08:56:03 -0700 IronPort-SDR: OCQDBZ8qyX1XvczNrlbYKWiHjMM2g6rtN2kV2we5KQVKpiG/feCrNs086zg4CafHB7MCPAPc58 Rf1mUMANtZ2g== X-IronPort-AV: E=Sophos;i="5.77,383,1596524400"; d="scan'208";a="464719044" Received: from bricha3-mobl.ger.corp.intel.com ([10.252.54.208]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-SHA; 16 Oct 2020 08:56:02 -0700 Date: Fri, 16 Oct 2020 16:55:58 +0100 From: Bruce Richardson To: David Marchand Cc: dev , Ma Lihong , Hemant Agrawal Message-ID: <20201016155558.GB1121@bricha3-MOBL.ger.corp.intel.com> References: <20200825114447.135030-1-bruce.richardson@intel.com> <20200903144942.671870-1-bruce.richardson@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Subject: Re: [dpdk-dev] [PATCH v2 0/3] Allow overriding of build-time constants 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 Fri, Oct 16, 2020 at 05:47:45PM +0200, David Marchand wrote: > Hello Bruce, > > On Thu, Sep 3, 2020 at 4:50 PM Bruce Richardson > wrote: > > > > A number of the more advanced DPDK build settings which are not expected to > > be user modified are stored in config/rte_config.h. In some cases, for a > > custom build a user may want to override those settings via CFLAGS, so we > > need to ensure that the definitions do not override the user-provided > > values. > > > > Bruce Richardson (3): > > config: remove explicit undefinition of unset values > > config: allow overriding some build defaults > > doc: add notes on overriding extra config values > > $ CFLAGS="-DRTE_MAX_MEMSEG_LISTS=64" meson setup > --default-library=shared --buildtype=debugoptimized > -Dprefix=/home/dmarchan/git/pub/dpdk.org/build/install build > $ ninja-build -C build -j4 install > > > librte_eal.so is indeed built with the 64 value: > $ pahole -C rte_mem_config build/install/lib64/librte_eal.so |grep memsegs > die__process_function: tag not supported (INVALID)! > struct rte_memseg_list memsegs[64]; /* 136 8704 */ > > > But no trace of the custom value for external applications: > $ grep -r RTE_MAX_MEMSEG_LISTS build/install > build/install/include/rte_config.h:#ifndef RTE_MAX_MEMSEG_LISTS > build/install/include/rte_config.h:#define RTE_MAX_MEMSEG_LISTS 128 > Binary file build/install/lib64/librte_eal.a matches > Binary file build/install/lib64/librte_eal.so.21.0 matches > > I can see the same using the meson option -Dc_args. > Good point, I had not thought of external apps using these values. They are mostly for internal use, so maybe its worthwhile looking to not have them in a public header file. What do you think? Is it likely that apps would be using some of these values, or needs to know the specifics? /Bruce