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 AE396A0546; Tue, 25 May 2021 11:22:56 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 2302C40150; Tue, 25 May 2021 11:22:56 +0200 (CEST) Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by mails.dpdk.org (Postfix) with ESMTP id 3A57E4003F for ; Tue, 25 May 2021 11:22:53 +0200 (CEST) IronPort-SDR: Rm5Wx3gCNmhi+jAyGjVWZ/orxcMiP8KOzzZWe2MuEeum1Gq84iU1zkybpxg+iQ3OoUCOYdpT96 cfj9SbTgppBA== X-IronPort-AV: E=McAfee;i="6200,9189,9994"; a="202165580" X-IronPort-AV: E=Sophos;i="5.82,328,1613462400"; d="scan'208";a="202165580" Received: from orsmga006.jf.intel.com ([10.7.209.51]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 May 2021 02:22:51 -0700 IronPort-SDR: L6zrtKLh1I/iwwrstQ1ht2ayoibOOqzdIBx2JOfaQAVM5MAiN7Hzm/wwMGKMX+ULKYIu6oKO1L gER0uRRPHNjA== X-IronPort-AV: E=Sophos;i="5.82,328,1613462400"; d="scan'208";a="397287452" Received: from bricha3-mobl.ger.corp.intel.com ([10.252.6.111]) by orsmga006-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-SHA; 25 May 2021 02:22:49 -0700 Date: Tue, 25 May 2021 10:22:45 +0100 From: Bruce Richardson To: Muhammad Ahmad Cc: dev@dpdk.org, ferruh.yigit@intel.com, qi.z.zhang@intel.com, konstantin.ananyev@intel.com, jia.guo@intel.com, beilei.xing@intel.com Message-ID: References: <20210525065818.10379-1-muhammad.ahmad@emumba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210525065818.10379-1-muhammad.ahmad@emumba.com> Subject: Re: [dpdk-dev] [RFC] Add selection between vector and scalar mode in ixgbe 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 Sender: "dev" On Tue, May 25, 2021 at 11:58:18AM +0500, Muhammad Ahmad wrote: > > The selection between scalar mode and vector mode was removed for > ixgbe driver in DPDK 20.02. The code base still has code > for scalar mode but it cannot be selected at compile time. The > vector mode is adequate for applications which require high > throughput which is the case most of the time, but scalar mode has > a use case in ultra-low-latency fintech applications for algorithmic > trading. This use case was also presented at the DPDK userspace > summit in September 2020. > This patch enables the ability to select between scalar and vector > modes for ixgbe drivers in the config. > In the future we can introduce API in ehtdev, which allow user to > select between latency and throughput mode. > > Signed-off-by: Muhammad Ahmad > --- Rather than having compile-time selection, this should be supported via runtime selection, using the force-max-simd-bitwidth flag. Setting the flag to 64 should force scalar paths. Regards, /Bruce