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 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,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,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 E6427C433E0 for ; Mon, 15 Feb 2021 00:40:31 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id AA78A64D5D for ; Mon, 15 Feb 2021 00:40:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AA78A64D5D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lunn.ch Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID: Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=WaIf7fxiFVZ/sPxTY+J10A8pnGr2To7PabCmAkLuRjk=; b=3Dq+u015iSoCINZS9f1SDCNij jUpoic+q6kc5ulHV/g/LxLlQrNLMmi4dwtFYVh01iqhC3R7NzanEdsXGtNvKSPT6xK3+x44CA0MBo idDYu4KU9LhRzpb9njekAhNkdzfq5gFblLMi9wK3GjCiRKiNYE5oFpZr+rCsFRuvbBYz0FuRtS0Ho Qi7JZlHlgGwxFiookDT5N2edg5Wzaq5icwqfwWY3h0MMtZM/VBkeEiBHy5Wl2jvRYW7vVvduuGQLW 8zSYw8AxpXLV3kUDSwxUv/6+I+VxBgz+Was7aRR9HcjzfzI/22jGaZ2yBHMMyOBDQmvaJEIRkj+eY wN5Ifau9w==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1lBRuq-0005aU-Uk; Mon, 15 Feb 2021 00:39:04 +0000 Received: from vps0.lunn.ch ([185.16.172.187]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1lBRuo-0005Zy-As for linux-arm-kernel@lists.infradead.org; Mon, 15 Feb 2021 00:39:03 +0000 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 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-Disposition: inline In-Reply-To: X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210214_193902_467758_E75F180A X-CRM114-Status: GOOD ( 12.23 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "devicetree@vger.kernel.org" , Yan Markman , "gregory.clement@bootlin.com" , "netdev@vger.kernel.org" , "atenart@kernel.org" , "linux-kernel@vger.kernel.org" , "linux@armlinux.org.uk" , Nadav Haklai , "rmk+kernel@armlinux.org.uk" , "robh+dt@kernel.org" , "thomas.petazzoni@bootlin.com" , "kuba@kernel.org" , Marcin Wojtas , David Miller , "linux-arm-kernel@lists.infradead.org" , "sebastian.hesselbarth@gmail.com" Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.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 u= p? > > 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=A0the number of pools reduced from 16 to = 8. > The current driver uses only 4pools, but some future features like QoS ca= n use over 4 pools.=A0 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 _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel