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=-11.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS 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 ADC83C43461 for ; Sun, 13 Sep 2020 07:13:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4EC02207EA for ; Sun, 13 Sep 2020 07:13:32 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599981212; bh=hEcvB93viN39eNdE0lOEHdm3EYuRbX/METemIvl9clw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=C7ah5PgZ4NkeqxD5wKOpa3viPUUSI9UWCpks9/sFh1xvnbPleane10Pw6AmM1l81E kM3OOMJpHyuY26GjBHWvydtHwhJO7KxQWPIlUC+dsxhdsni+KY5Y4EJIOuqZpGxyp8 b0L3V5yG7MQZeDTAM9ZfZrGRgvgmrkJIE7R241Q8= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725923AbgIMHNb (ORCPT ); Sun, 13 Sep 2020 03:13:31 -0400 Received: from mail.kernel.org ([198.145.29.99]:42638 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725910AbgIMHNb (ORCPT ); Sun, 13 Sep 2020 03:13:31 -0400 Received: from localhost (unknown [213.57.247.131]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 63712207C3; Sun, 13 Sep 2020 07:13:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1599981210; bh=hEcvB93viN39eNdE0lOEHdm3EYuRbX/METemIvl9clw=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=Ssj/lDCFEiDXB70VrFbb0t0bup0n2CDHe7VDSfk219UdSihivOjnQJ4R7TGZR8jkJ fP9f1YtRbqhmQcjZpH4JY6VvENIvQep6gGIBp2t4uYSx7NNjAm7VHKGYAsV8/u80+d CtuFiLOzo7bAr011kQk3Gghck51P6kC7UEGwfhdE= Date: Sun, 13 Sep 2020 10:13:25 +0300 From: Leon Romanovsky To: Potnuri Bharat Teja 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: <20200913071325.GC35718@unreal> References: <20200909134726.10348-1-bharat@chelsio.com> <20200910122739.GJ421756@unreal> <20200911131152.GM421756@unreal> <20200911160951.GA20264@chelsio.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200911160951.GA20264@chelsio.com> Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Fri, Sep 11, 2020 at 09:39:57PM +0530, Potnuri Bharat Teja wrote: > 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. So why doesn't rdma-core have dack_mode=0 in kernel-boot scripts? Thanks