From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: <SRS0+2Fq3=NR=ericsson.com=mattias.ronnblom@lysator.liu.se> Received: from mail.lysator.liu.se (mail.lysator.liu.se [130.236.254.3]) by dpdk.org (Postfix) with ESMTP id 37C702BE2; Tue, 6 Nov 2018 12:03:29 +0100 (CET) Received: from mail.lysator.liu.se (localhost [127.0.0.1]) by mail.lysator.liu.se (Postfix) with ESMTP id B56F640022; Tue, 6 Nov 2018 12:03:28 +0100 (CET) Received: by mail.lysator.liu.se (Postfix, from userid 1004) id A228740021; Tue, 6 Nov 2018 12:03:28 +0100 (CET) X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on bernadotte.lysator.liu.se X-Spam-Level: X-Spam-Status: No, score=-0.9 required=5.0 tests=ALL_TRUSTED,AWL autolearn=disabled version=3.4.1 X-Spam-Score: -0.9 Received: from [192.168.1.59] (host-90-232-59-122.mobileonline.telia.com [90.232.59.122]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.lysator.liu.se (Postfix) with ESMTPSA id 3079640016; Tue, 6 Nov 2018 12:03:26 +0100 (CET) To: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>, Thomas Monjalon <thomas@monjalon.net>, Jerin Jacob <jerin.jacob@caviumnetworks.com> Cc: "Gavin Hu (Arm Technology China)" <Gavin.Hu@arm.com>, "dev@dpdk.org" <dev@dpdk.org>, "stable@dpdk.org" <stable@dpdk.org>, Ola Liljedahl <Ola.Liljedahl@arm.com>, "olivier.matz@6wind.com" <olivier.matz@6wind.com>, "chaozhu@linux.vnet.ibm.com" <chaozhu@linux.vnet.ibm.com>, "bruce.richardson@intel.com" <bruce.richardson@intel.com>, "konstantin.ananyev@intel.com" <konstantin.ananyev@intel.com>, nd <nd@arm.com> References: <1537172244-64874-2-git-send-email-gavin.hu@arm.com> <1874944.OrACW1nkDZ@xps> <20181027150024.GA2294@jerin> <17713879.gC9jYcxDUo@xps> <HE1PR0701MB239463577089E46983B2371CE1C80@HE1PR0701MB2394.eurprd07.prod.outlook.com> <AM6PR08MB3672A936960FCEACC700AB1498CA0@AM6PR08MB3672.eurprd08.prod.outlook.com> From: =?UTF-8?Q?Mattias_R=c3=b6nnblom?= <mattias.ronnblom@ericsson.com> Message-ID: <ff686db3-82e4-c3ae-0a61-1200da97faf6@ericsson.com> Date: Tue, 6 Nov 2018 12:03:25 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.2.1 MIME-Version: 1.0 In-Reply-To: <AM6PR08MB3672A936960FCEACC700AB1498CA0@AM6PR08MB3672.eurprd08.prod.outlook.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Virus-Scanned: ClamAV using ClamSMTP Subject: Re: [dpdk-stable] [dpdk-dev] [PATCH 1/2] ring: synchronize the load and store of the tail X-BeenThere: stable@dpdk.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: patches for DPDK stable branches <stable.dpdk.org> List-Unsubscribe: <https://mails.dpdk.org/options/stable>, <mailto:stable-request@dpdk.org?subject=unsubscribe> List-Archive: <http://mails.dpdk.org/archives/stable/> List-Post: <mailto:stable@dpdk.org> List-Help: <mailto:stable-request@dpdk.org?subject=help> List-Subscribe: <https://mails.dpdk.org/listinfo/stable>, <mailto:stable-request@dpdk.org?subject=subscribe> X-List-Received-Date: Tue, 06 Nov 2018 11:03:29 -0000 On 2018-11-05 22:51, Honnappa Nagarahalli wrote: >> I've also run an out-of-tree DSW throughput benchmark, and I've found that >> going from Non-C11 to C11 gives a 4% slowdown. After this patch, the >> slowdown is only 2,8%. > This is interesting. The general understanding seems to be that C11 atomics should not add any additional instructions on x86. But, we still see some drop in performance. Is this attributed to compiler not being allowed to re-order? > I was lazy enough not to disassemble, so I don't know. I would suggest non-C11 mode stays as the default on x86_64.