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=-5.0 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 E0100C56202 for ; Mon, 23 Nov 2020 15:52:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 602B520B1F for ; Mon, 23 Nov 2020 15:52:16 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="lNFVhTRm" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732751AbgKWPvz (ORCPT ); Mon, 23 Nov 2020 10:51:55 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58900 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731987AbgKWPvy (ORCPT ); Mon, 23 Nov 2020 10:51:54 -0500 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [IPv6:2001:4d48:ad52:32c8:5054:ff:fe00:142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5EDD6C0613CF; Mon, 23 Nov 2020 07:51:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=Bj8IsgcBUP1tMlbxsnt+v78ZaLFATDewDNz07x7jB8E=; b=lNFVhTRmgDvSLwPcVyLjphrWX yrDoxWB9bc32VqepIvRNt0LpSSLM8Mkl+FKitGFVDpiGfHs5tFtiHQpZWgoy952o8fUiyIR7aqDp7 +TP/4sppx4NjqKQ5efNUqZQomo8dQv1nYeL1Ug/GGQbFBI0CaV0mqQ1NwX1tJ5cNCmrraHwFB7AhD wWKatgkFf+PfSDGYgL0rZb+vQkOPFhKGgGB1DYkDhoX6lMoqUxXLfU2bXUAd25aSv8QscBo3V3ClO kFg2lic1ywy6UTpm7KbDSEm6q02hsycgkA8JP7kG3BfT6PVj6gfST0p/lPq8jVCs5S09sidbXe/z3 m70yNM4aw==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:35116) by pandora.armlinux.org.uk with esmtpsa (TLS1.3:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1khE87-0006CQ-Fh; Mon, 23 Nov 2020 15:51:51 +0000 Received: from linux by shell.armlinux.org.uk with local (Exim 4.92) (envelope-from ) id 1khE84-0006RU-Ly; Mon, 23 Nov 2020 15:51:48 +0000 Date: Mon, 23 Nov 2020 15:51:48 +0000 From: Russell King - ARM Linux admin To: Stefan Chulski Cc: "netdev@vger.kernel.org" , "thomas.petazzoni@bootlin.com" , "davem@davemloft.net" , Nadav Haklai , Yan Markman , "linux-kernel@vger.kernel.org" , "kuba@kernel.org" , "mw@semihalf.com" , "andrew@lunn.ch" Subject: Re: [EXT] Re: [PATCH v1] net: mvpp2: divide fifo for dts-active ports only Message-ID: <20201123155148.GX1551@shell.armlinux.org.uk> References: <1606143160-25589-1-git-send-email-stefanc@marvell.com> <20201123151049.GV1551@shell.armlinux.org.uk> <20201123153332.GW1551@shell.armlinux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.10.1 (2018-07-13) Sender: Russell King - ARM Linux admin Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Nov 23, 2020 at 03:44:05PM +0000, Stefan Chulski wrote: > > > > On Mon, Nov 23, 2020 at 04:52:40PM +0200, stefanc@marvell.com wrote: > > > > > From: Stefan Chulski > > > > > > > > > > Tx/Rx FIFO is a HW resource limited by total size, but shared by > > > > > all ports of same CP110 and impacting port-performance. > > > > > Do not divide the FIFO for ports which are not enabled in DTS, so > > > > > active ports could have more FIFO. > > > > > > > > > > The active port mapping should be done in probe before FIFO-init. > > > > > > > > It would be nice to know what the effect is from this - is it a > > > > small or large boost in performance? > > > > > > I didn't saw any significant improvement with LINUX bridge or > > > forwarding, but this reduced PPv2 overruns drops, reduced CRC sent errors > > with DPDK user space application. > > > So this improved zero loss throughput. Probably with XDP we would see a > > similar effect. > > > > > > > What is the effect when the ports on a CP110 are configured for 10G, > > > > 1G, and 2.5G in that order, as is the case on the Macchiatobin board? > > > > > > Macchiatobin has two CP's. CP1 has 3 ports, so the distribution of FIFO would > > be the same as before. > > > On CP0 which has a single port, all FIFO would be allocated for 10G port. > > > > Your code allocates for CP1: > > > > 32K to port 0 (the 10G port on Macchiatobin) 8K to port 1 (the 1G dedicated > > ethernet port on Macchiatobin) 4K to port 2 (the 1G/2.5G SFP port on > > Macchiatobin) > > > > I'm questioning that allocation for port 1 and 2. > > Yes, but this allocation exists also in current code. > From HW point of view(MAC and PPv2) maximum supported speed > in CP110: port 0 - 10G, port 1 - 2.5G, port 2 - 2.5G. > in CP115: port 0 - 10G, port 1 - 5G, port 2 - 2.5G. > > So this allocation looks correct at least for CP115. > Problem that we cannot reallocate FIFO during runtime, after specific speed negotiation. We could do much better. DT has a "max-speed" property for ethernet controllers. If we have that property, then I think we should use that to determine the initialisation time FIFO allocation. As I say, on Macchiatobin, the allocations we end up with are just crazy when you consider the port speeds that the hardware supports. Maybe that should be done as a follow-on patch - but I think it needs to be done. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 40Mbps down 10Mbps up. Decent connectivity at last!