From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pg0-f42.google.com (mail-pg0-f42.google.com [74.125.83.42]) by dpdk.org (Postfix) with ESMTP id 639741B670 for ; Fri, 3 Nov 2017 03:55:50 +0100 (CET) Received: by mail-pg0-f42.google.com with SMTP id b192so1316628pga.2 for ; Thu, 02 Nov 2017 19:55:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:from:to:cc:references:message-id:date:user-agent :mime-version:in-reply-to:content-transfer-encoding; bh=32Uy0z4lWHx8F3AXRWbN4Lg4E1y2FqxgCv4op7fviQs=; b=qw7cnPq1Bg/MAwvbVhqNj8Ajz5vtxeFpIZtiSg1mXug1S/ev0fCsXQZzPcUsGOVifw W3uuUX98pds1a4dbQVOxLR+zKT8ei9PtVbHemFgvNH0P3Tq9eBKJ4B8qKvrToWP7Sm6u yNT2Sd8Ho+ujgOc0yRyUfUIuUvz9kBCUqSf9D5Enh80iS6qzd4LLAEVZ93WuyaRm92FU FUXq7BZgfS8gaKcOnimaSjH5OTcM8RDVDQBmEIxLCY65zW3FgaPcPdolJ/Qr96fZhPsR 3wpcv4ZRvWRD70wdh3dkB2R50ryTL8/MzZmYYTdNgx4Cx/OirvAqIicKao0oGwNBO3za tFqA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:from:to:cc:references:message-id:date :user-agent:mime-version:in-reply-to:content-transfer-encoding; bh=32Uy0z4lWHx8F3AXRWbN4Lg4E1y2FqxgCv4op7fviQs=; b=oGOK5HU+3bB79Jy4FYfhAVSfX7MQp+nCE9U9R05dvwCdW3rzYDrMs/WiqXL1pPJrVR fvvdGLcLzhfP7syCYVY+BWDaRhu6vauY3gwChzVqX2zxW18k6wEF488Ngkg+76xdAKQQ A0Q3aR2y5WCDc0fFuPMA6vzSHiT0IMcnFYWETEHHR93tEtCpbEAScfz4bqJ0C3wpcAhT /7BuHuWkMc/tSWlzxktnyYo8ssu6Ezi6t/u4dgD4ddqgK2HfZlN5xmkcOdhk5ADUnuoR XiT5xEFNKH6PjIEofr2wRM/rSpsV3qLTOJcoSESH2JZg1GbgQEQujfirhz98ypODMF7c KazQ== X-Gm-Message-State: AMCzsaU3pGyw+bxylmFoUkrJ6Ay+1HSWo8Ai4gBE1hGQ/O3/1Cc0mjip wBb3z/mEippBUy9GXNvS1gA= X-Google-Smtp-Source: ABhQp+RSBjKJ6fxAZ08Y3tt15Y/84BbBxb9He+xwOFxOe4Q+YK6yUA7kDVO48ojRi+9ac9myhfaSKw== X-Received: by 10.159.244.138 with SMTP id y10mr5307613plr.399.1509677749585; Thu, 02 Nov 2017 19:55:49 -0700 (PDT) Received: from [0.0.0.0] (67.209.179.165.16clouds.com. [67.209.179.165]) by smtp.gmail.com with ESMTPSA id u46sm7719610pgn.80.2017.11.02.19.55.41 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 02 Nov 2017 19:55:48 -0700 (PDT) From: Jia He To: Jerin Jacob Cc: "Ananyev, Konstantin" , "Zhao, Bing" , Olivier MATZ , "dev@dpdk.org" , "jia.he@hxt-semitech.com" , "jie2.liu@hxt-semitech.com" , "bing.zhao@hxt-semitech.com" , "Richardson, Bruce" , jianbo.liu@arm.com, hemant.agrawal@nxp.com References: <2601191342CEEE43887BDE71AB9772585FAAB570@IRSMSX103.ger.corp.intel.com> <3e580cd7-2854-d855-be9c-7c4ce06e3ed5@gmail.com> <20171020054319.GA4249@jerin> <20171023100617.GA17957@jerin> <20171025132642.GA13977@jerin> <20171031111433.GA21742@jerin> <69adfb00-4582-b362-0540-d1d9d6bcf6aa@gmail.com> <20171101190420.GA21407@jerin> <8bc4095d-301e-3e99-9644-27848d97e9bc@gmail.com> Message-ID: Date: Fri, 3 Nov 2017 10:55:40 +0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <8bc4095d-301e-3e99-9644-27848d97e9bc@gmail.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Subject: Re: [dpdk-dev] [PATCH] ring: guarantee ordering of cons/prod loading when doing enqueue/dequeue 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: , X-List-Received-Date: Fri, 03 Nov 2017 02:55:50 -0000 Hi Jerin On 11/2/2017 4:57 PM, Jia He Wrote: > > Hi， Jerin > please see my performance test below > On 11/2/2017 3:04 AM, Jerin Jacob Wrote: > [...] >> Should it be like instead? >> >> +#else >> +        *old_head = __atomic_load_n(&r->cons.head, __ATOMIC_ACQUIRE); >> +        const uint32_t prod_tail = __atomic_load_n(&r->prod.tail, >> __ATOMIC_ACQUIRE); >> It would be nice to see how much overhead it gives.ie back to back >> __ATOMIC_ACQUIRE. > I can NOT test ring_perf_autotest in our server because of the > something wrong in PMU counter. > All the return value of rte_rdtsc is 0 with and without your provided > ko module. I am still > investigating the reason. > Hi Jerin As for the root cause of rte_rdtsc issue, it might be due to the pmu counter frequency is too low in our arm64 server("Amberwing" from qualcom) [586990.057779] arch_timer_get_cntfrq()=20000000 Only 20MHz instead of 100M/200MHz, and CNTFRQ_EL0 is not even writable in kernel space. Maybe the code in ring_perf_autotest needs to be changed? e.g.     printf("SC empty dequeue: %.2F\n",             (double)(sc_end-sc_start) / iterations);     printf("MC empty dequeue: %.2F\n",             (double)(mc_end-mc_start) / iterations); Otherwise it is always 0 if the time difference divides by iterations. -- Cheers, Jia