From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EF927C433E2 for ; Fri, 11 Sep 2020 16:10:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C7054206CA for ; Fri, 11 Sep 2020 16:10:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726580AbgIKQKH (ORCPT ); Fri, 11 Sep 2020 12:10:07 -0400 Received: from stargate.chelsio.com ([12.32.117.8]:58450 "EHLO stargate.chelsio.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726546AbgIKQKF (ORCPT ); Fri, 11 Sep 2020 12:10:05 -0400 Received: from localhost ([10.193.186.242]) by stargate.chelsio.com (8.13.8/8.13.8) with ESMTP id 08BG9vsl019190; Fri, 11 Sep 2020 09:09:58 -0700 Date: Fri, 11 Sep 2020 21:39:57 +0530 From: Potnuri Bharat Teja To: Leon Romanovsky Cc: "jgg@ziepe.ca" , "dledford@redhat.com" , "linux-rdma@vger.kernel.org" Subject: Re: [PATCH] RDMA/iw_cxgb4: disable delayed ack by default Message-ID: <20200911160951.GA20264@chelsio.com> References: <20200909134726.10348-1-bharat@chelsio.com> <20200910122739.GJ421756@unreal> <20200911131152.GM421756@unreal> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200911131152.GM421756@unreal> User-Agent: Mutt/1.5.24 (2015-08-30) Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Friday, September 09/11/20, 2020 at 18:41:52 +0530, Leon Romanovsky wrote: > On Thu, Sep 10, 2020 at 07:14:50PM +0000, Potnuri Bharat Teja wrote: > > >> Subject: [PATCH] RDMA/iw_cxgb4: disable delayed ack by default > > >> > > >> Receive side delayed ack mode is needed only for certain area networks/ connections. Therefore disable it by default. > > >> > > >> Signed-off-by: Potnuri Bharat Teja > > >> --- > > >> drivers/infiniband/hw/cxgb4/cm.c | 4 ++-- > > >> 1 file changed, 2 insertions(+), 2 deletions(-) > > >> > > >> diff --git a/drivers/infiniband/hw/cxgb4/cm.c b/drivers/infiniband/hw/cxgb4/cm.c > > >> index 1f288c73ccfc..8769e7aa097f 100644 > > >> --- a/drivers/infiniband/hw/cxgb4/cm.c > > >> +++ b/drivers/infiniband/hw/cxgb4/cm.c > > >> @@ -77,9 +77,9 @@ static int enable_ecn; module_param(enable_ecn, int, 0644); MODULE_PARM_DESC(enable_ecn, "Enable ECN (default=0/disabled)"); > > >> > > >> -static int dack_mode = 1; > > >> +static int dack_mode; > > >> module_param(dack_mode, int, 0644); > > >> -MODULE_PARM_DESC(dack_mode, "Delayed ack mode (default=1)"); > > >> +MODULE_PARM_DESC(dack_mode, "Delayed ack mode (default=0)"); > > > > > >Are you sure that this doesn't break user scripts? > > Yes, I am sure. This does not interfere with user/kernel RDMA functionalities. > > How is it possible? > Before this change user that did "modprobe iw_cxgb4" had delayed mode > enabled, after this he will need to issue "modprobe iw_cxgb4 dack_mode=1" > Sorry I didnt get it right earlier. Yes now if user wants delayed ack mode, user can issue "modprobe iw_cxgb4 dack_mode=1" or change it dynamically via /sys/module/<>/paramters. Chelsio adapters for better performance in most cases needs delayed ack mode to be disabled. This change somehow got missed upstream all this while. In fewer explicit cases, user can enable delayed ack mode where it is needed. > https://github.com/linux-rdma/rdma-core/blob/master/kernel-boot/rdma-hw-modules.rules#L12 > > Thanks > > > > > Thanks, > > Bharat. > > > > > >Thanks > > > > > >> > > >> uint c4iw_max_read_depth = 32; > > >> module_param(c4iw_max_read_depth, int, 0644); > > >> -- > > >> 2.24.0