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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 2DDD3C433E6 for ; Mon, 15 Feb 2021 00:39:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DE2FC64DC4 for ; Mon, 15 Feb 2021 00:39:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230090AbhBOAjb (ORCPT ); Sun, 14 Feb 2021 19:39:31 -0500 Received: from vps0.lunn.ch ([185.16.172.187]:42034 "EHLO vps0.lunn.ch" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229818AbhBOAj3 (ORCPT ); Sun, 14 Feb 2021 19:39:29 -0500 Received: from andrew by vps0.lunn.ch with local (Exim 4.94) (envelope-from ) id 1lBRuQ-006M9V-Uo; Mon, 15 Feb 2021 01:38:38 +0100 Date: Mon, 15 Feb 2021 01:38:38 +0100 From: Andrew Lunn To: Stefan Chulski Cc: Marcin Wojtas , David Miller , "netdev@vger.kernel.org" , "thomas.petazzoni@bootlin.com" , Nadav Haklai , Yan Markman , "linux-kernel@vger.kernel.org" , "kuba@kernel.org" , "linux@armlinux.org.uk" , "rmk+kernel@armlinux.org.uk" , "atenart@kernel.org" , "devicetree@vger.kernel.org" , "robh+dt@kernel.org" , "sebastian.hesselbarth@gmail.com" , "gregory.clement@bootlin.com" , "linux-arm-kernel@lists.infradead.org" Subject: Re: [EXT] Re: [PATCH v12 net-next 12/15] net: mvpp2: add BM protection underrun feature support Message-ID: References: <1612950500-9682-1-git-send-email-stefanc@marvell.com> <1612950500-9682-13-git-send-email-stefanc@marvell.com> <20210210.152924.767175240247395907.davem@davemloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > Does this even need to be configurable? What is the cost of turning it on? > > How does having less pools affect the system? Does average latency go up? > > When would i consider an underrun actually a good thing? > > > > Maybe it should just be hard coded on? Or we should try to detect when > > underruns are happening a lot, and dynamically turn it on for a while? > > > The cost of this change is that the number of pools reduced from 16 to 8. > The current driver uses only 4pools, but some future features like QoS can use over 4 pools.  So you are saying, there is currently no cost for turning it on. So it seems like you should just turn it on, and forget the module parameter. When QoS features are added which require more than 8 pools you can then address the issue of if this should be configurable. Andrew