From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?iso-8859-1?Q?N=E9lio?= Laranjeiro Subject: Re: [PATCH v2] net/mlx5: fix Tx doorbell memory barrier Date: Wed, 25 Oct 2017 11:19:34 +0200 Message-ID: <20171025091934.hvf5fv4bpkzaba2u@laranjeiro-vm> References: <20171022080022.13528-1-yskoh@mellanox.com> <49c39b44917c35ecaabf06f5f920d0f7e0ed0b6b.1508891141.git.yskoh@mellanox.com> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Cc: adrien.mazarguil@6wind.com, dev@dpdk.org, stable@dpdk.org, Sagi Grimberg , Alexander Solganik To: Yongseok Koh Return-path: Received: from mail-wm0-f65.google.com (mail-wm0-f65.google.com [74.125.82.65]) by dpdk.org (Postfix) with ESMTP id 277FD1B945 for ; Wed, 25 Oct 2017 11:19:37 +0200 (CEST) Received: by mail-wm0-f65.google.com with SMTP id b189so506458wmd.4 for ; Wed, 25 Oct 2017 02:19:37 -0700 (PDT) Content-Disposition: inline In-Reply-To: <49c39b44917c35ecaabf06f5f920d0f7e0ed0b6b.1508891141.git.yskoh@mellanox.com> 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, Oct 24, 2017 at 05:27:25PM -0700, Yongseok Koh wrote: > Configuring UAR as IO-mapped makes maximum throughput decline by noticeable > amount. If UAR is configured as write-combining register, a write memory > barrier is needed on ringing a doorbell. rte_wmb() is mostly effective when > the size of a burst is comparatively small. Revert the register back to > write-combining and enforce a write memory barrier instead, except for > vectorized Tx burst routines. Application can change it by setting > MLX5_SHUT_UP_BF under its own necessity. > > Fixes: 9f9bebae5530 ("net/mlx5: don't map doorbell register to write combining") > Cc: stable@dpdk.org > Cc: Sagi Grimberg > Cc: Alexander Solganik > > Signed-off-by: Yongseok Koh > Acked-by: Shahaf Shuler Acked-by: Nelio Laranjeiro Thanks, -- Nélio Laranjeiro 6WIND