From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: <dev-bounces@dpdk.org> Received: from dpdk.org (dpdk.org [92.243.14.124]) by inbox.dpdk.org (Postfix) with ESMTP id 1516AA2EEB for <public@inbox.dpdk.org>; Mon, 7 Oct 2019 17:57:54 +0200 (CEST) Received: from [92.243.14.124] (localhost [127.0.0.1]) by dpdk.org (Postfix) with ESMTP id 4F5261C1C6; Mon, 7 Oct 2019 17:57:53 +0200 (CEST) Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by dpdk.org (Postfix) with ESMTP id 000A61C1C2 for <dev@dpdk.org>; Mon, 7 Oct 2019 17:57:50 +0200 (CEST) X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 07 Oct 2019 08:57:49 -0700 X-IronPort-AV: E=Sophos;i="5.67,268,1566889200"; d="scan'208";a="187026371" Received: from bricha3-mobl.ger.corp.intel.com ([10.237.221.95]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 07 Oct 2019 08:57:47 -0700 Date: Mon, 7 Oct 2019 16:57:44 +0100 From: Bruce Richardson <bruce.richardson@intel.com> To: Andrzej Ostruszka <amo@semihalf.com> Cc: dev@dpdk.org, Thomas Monjalon <thomas@monjalon.net>, Ray Kinsella <mdr@ashroe.eu>, Neil Horman <nhorman@tuxdriver.com>, bluca@debian.org Message-ID: <20191007155744.GB1850@bricha3-MOBL.ger.corp.intel.com> References: <20190927194932.22197-1-bruce.richardson@intel.com> <20190927205931.23022-1-bruce.richardson@intel.com> <20190927205931.23022-3-bruce.richardson@intel.com> <e0e68877-27e3-28a1-21f1-4fa1b413b6b8@semihalf.com> <20191001165305.GA1899@bricha3-MOBL.ger.corp.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191001165305.GA1899@bricha3-MOBL.ger.corp.intel.com> User-Agent: Mutt/1.11.4 (2019-03-13) Subject: Re: [dpdk-dev] [PATCH v2 2/2] build: support building ABI versioned files twice X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: DPDK patches and discussions <dev.dpdk.org> List-Unsubscribe: <https://mails.dpdk.org/options/dev>, <mailto:dev-request@dpdk.org?subject=unsubscribe> List-Archive: <http://mails.dpdk.org/archives/dev/> List-Post: <mailto:dev@dpdk.org> List-Help: <mailto:dev-request@dpdk.org?subject=help> List-Subscribe: <https://mails.dpdk.org/listinfo/dev>, <mailto:dev-request@dpdk.org?subject=subscribe> Errors-To: dev-bounces@dpdk.org Sender: "dev" <dev-bounces@dpdk.org> On Tue, Oct 01, 2019 at 05:53:05PM +0100, Bruce Richardson wrote: > On Tue, Oct 01, 2019 at 03:23:47PM +0200, Andrzej Ostruszka wrote: > > Thanks Bruce for the patch. I like the idea of splitting versioning out > > of rte_compat.h, but I have some comments. > > > > On 9/27/19 10:59 PM, Bruce Richardson wrote: > > [...] > > > --- a/config/common_base > > > +++ b/config/common_base > > > @@ -111,6 +111,7 @@ CONFIG_RTE_MAX_VFIO_CONTAINERS=64 > > > CONFIG_RTE_MALLOC_DEBUG=n > > > CONFIG_RTE_EAL_NUMA_AWARE_HUGEPAGES=n > > > CONFIG_RTE_USE_LIBBSD=n > > > +CONFIG_RTE_USE_FUNCTION_VERSIONING=y > > > > I'm not fond of this config option - it is not really an option to be > > changed by the user. I would prefer to just add flag to CFLAGS in > > mk/target/generic/rte.vars.mk. > > > > Ok, that sounds reasonable enough. Done in V3. > > > > # > > > # Recognize/ignore the AVX/AVX512 CPU flags for performance/power testing. > > > diff --git a/config/rte_config.h b/config/rte_config.h > > > index 0bbbe274f..b63a2fdea 100644 > > > --- a/config/rte_config.h > > > +++ b/config/rte_config.h > > > @@ -31,9 +31,6 @@ > > > > > > /****** library defines ********/ > > > > > > -/* compat defines */ > > > -#define RTE_BUILD_SHARED_LIB > > > - > > > > So now everything builds "as static lib" (but with "-fPIC") apart from > > those libraries that use symbol versioning. I'm OK with that however > > I'd like to note that code might be using RTE_BUILD_SHARED_LIB and do > > different things e.g. app/test-bbdev/test_bbdev_perf.c. I know that was > > already the case - just wanted to say that aloud to make sure we are all > > aware of this :). > > Thanks for pointing this out, I wasn't aware of it! Doing a git grep this > seems to be the only place in a C file (other than rte_config.h and > rte_compat.h) where the SHARED_LIB flag is being checked. I'll need to > follow up on that to see what the logic is there, because it seems strange > to require such a check. > This #ifdef can be removed, see patchset: http://patches.dpdk.org/project/dpdk/list/?series=6699 This then leaves function versioning as the only use-case where we need different code paths for static vs shared builds. > > > > > diff --git a/doc/guides/contributing/coding_style.rst b/doc/guides/contributing/coding_style.rst > > > index 449b33494..e95a1a2be 100644 > > > --- a/doc/guides/contributing/coding_style.rst > > > +++ b/doc/guides/contributing/coding_style.rst > > > @@ -948,6 +948,13 @@ reason > > > built. For missing dependencies this should be of the form > > > ``'missing dependency, "libname"'``. > > > > > > +use_function_versioning > > > + **Default Value = false**. > > > + Specifies if the library in question has ABI versioned functions. If it > > > + has, this value should be set to ensure that the C files are compiled > > > + twice with suitable parameters for each of shared or static library > > > + builds. > > > + > > > > Maybe a different name for this option? In general an "ideal > > theoretical" solution would be for build system to figure out on its own > > that separate build is necessary automatically - but that might incur > > some performance penalty (additional grep'ing of sources or so). > > I was thinking about that, and how we can do it automatically. The trouble > is that for correctness we would need to recheck every file after it had > changed, and since the result of the check means that we have different > build steps it would basically mean doing a full reconfiguration for every > file change. That's not really practical, hence this proposed solution. > I've not made any changes here for the V3. However, if we want to reduce the number of changes required, we could always switch to having the rte_function_versioning.h header file included on the basis of the flag in the meson.build file. Having the C flag compile vary based on the meson one is normal, having the inverse is problematic because of what I explained above - you'd basically need to reconfigure to check after each file change. Personally, I don't think changing things to auto-include the header is worth it, hence the fact of no-change in v3. Regards, /Bruce