From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id EDC7941BA3; Wed, 1 Feb 2023 22:41:14 +0100 (CET) Received: from mails.dpdk.org (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 866EC4067C; Wed, 1 Feb 2023 22:41:14 +0100 (CET) Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by mails.dpdk.org (Postfix) with ESMTP id 3A3BD4021D for ; Wed, 1 Feb 2023 22:41:12 +0100 (CET) Received: by linux.microsoft.com (Postfix, from userid 1086) id 52CE420B7102; Wed, 1 Feb 2023 13:41:11 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 52CE420B7102 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1675287671; bh=et9+J5NT3nPzDE3bsIh8eaTY6LZYjaQN6QkdThbDRYU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ouilF95eb+6aP/spGAtdl41mpJ1kSJsvIilffD54xziEa3YIf9eBKKWSV5dKJGc+c qmqp1UprTSy9MlKIfrYxiBgijMC1mnCP0wQjMGDawKP10IrASZBDizPRab+I+y0041 gFSmkaVICkhHH2h8s1vPustZDtHV4yhVCKyVG4sE= Date: Wed, 1 Feb 2023 13:41:11 -0800 From: Tyler Retzlaff To: Honnappa Nagarahalli Cc: "thomas@monjalon.net" , "dev@dpdk.org" , "bruce.richardson@intel.com" , "mb@smartsharesystems.com" , "david.marchand@redhat.com" , "jerinj@marvell.com" , "konstantin.ananyev@huawei.com" , "ferruh.yigit@amd.com" , nd Subject: Re: [PATCH] eal: introduce atomics abstraction Message-ID: <20230201214111.GA30564@linuxonhyperv3.guj3yctzbm1etfxqx2vob5hsef.xx.internal.cloudapp.net> References: <1673558785-24992-1-git-send-email-roretzla@linux.microsoft.com> <1673558785-24992-2-git-send-email-roretzla@linux.microsoft.com> <1844463.CQOukoFCf9@thomas> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) 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 On Wed, Feb 01, 2023 at 01:07:59AM +0000, Honnappa Nagarahalli wrote: > > > -----Original Message----- > > From: Thomas Monjalon > > Sent: Tuesday, January 31, 2023 4:42 PM > > To: Honnappa Nagarahalli > > Cc: dev@dpdk.org; bruce.richardson@intel.com; mb@smartsharesystems.com; > > Tyler Retzlaff ; david.marchand@redhat.com; > > jerinj@marvell.com; konstantin.ananyev@huawei.com; ferruh.yigit@amd.com > > Subject: Re: [PATCH] eal: introduce atomics abstraction > > > > Honnappa, please could you give your view on the future of atomics in DPDK? > Thanks Thomas, apologies it has taken me a while to get to this discussion. > > IMO, we do not need DPDK's own abstractions. APIs from stdatomic.h (stdatomics as is called here) already serve the purpose. These APIs are well understood and documented. i agree that whatever atomics APIs we advocate for should align with the standard C atomics for the reasons you state including implied semantics. > > For environments where stdatomics are not supported, we could have a stdatomic.h in DPDK implementing the same APIs (we have to support only _explicit APIs). This allows the code to use stdatomics APIs and when we move to minimum supported standard C11, we just need to get rid of the file in DPDK repo. my concern with this is that if we provide a stdatomic.h or introduce names from stdatomic.h it's a violation of the C standard. references: * ISO/IEC 9899:2011 sections 7.1.2, 7.1.3. * GNU libc manual https://www.gnu.org/software/libc/manual/html_node/Reserved-Names.html in effect the header, the names and in some instances namespaces introduced are reserved by the implementation. there are several reasons in the GNU libc manual that explain the justification for these reservations and if if we think about ODR and ABI compatibility we can conceive of others. i'll also remark that the inter-mingling of names from the POSIX standard implicitly exposed as a part of the EAL public API has been problematic for portability. let's discuss this from here. if there's still overwhelming desire to go this route then we'll just do our best. ty