From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from vps0.lunn.ch (vps0.lunn.ch [156.67.10.101]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id B79632BE634; Tue, 19 Aug 2025 16:04:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=156.67.10.101 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755619446; cv=none; b=JstfVktj3zNeVm2xzbWxwpg1jsTpBnao+FApG0claON6jPFYCuM+PTFPIzjHM5M8ShXcCfp/gPekVKmbJKNUUGbJWRNNT+B9M2c08RZfo3KVSZ5mHgilc6DT7RGsBFVG68A/+i+N087lQEg2D1gQyuJt5qtvTwn3iWRj4eIbmt8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1755619446; c=relaxed/simple; bh=wLvfu74oK9PGxpv8iFgmi36eU1aC/XOa2NPyXzmd7YE=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=sEsNpKPz0WCoueOllhINl9rmtH5uepzFNAFMtfEG0quSGPjwuQnQrMgitKGAT84vhp+Ekj1oZglZafi285+6B5+cOdj3QrlvvLHvLyQP8PmzWWxB8z2LOFWe5LfLyO1teoaBtShZrO9Ne4y3outgJJvA7S9Lrbolca2pXZbmp6A= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lunn.ch; spf=pass smtp.mailfrom=lunn.ch; dkim=pass (1024-bit key) header.d=lunn.ch header.i=@lunn.ch header.b=kGPqj6NC; arc=none smtp.client-ip=156.67.10.101 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=lunn.ch Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=lunn.ch Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=lunn.ch header.i=@lunn.ch header.b="kGPqj6NC" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lunn.ch; s=20171124; h=In-Reply-To:Content-Disposition:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:From:Sender:Reply-To:Subject: Date:Message-ID:To:Cc:MIME-Version:Content-Type:Content-Transfer-Encoding: Content-ID:Content-Description:Content-Disposition:In-Reply-To:References; bh=N+7flFK2RUnxDqXCVUqXaa0V2OFkhUFUQMezuL5yE6g=; b=kGPqj6NClAqPHS8M/uA71K3oTt 5MMCYBEUXDle2yjsuFbQEh7VjoHgYOYDaXwJePFOVYZZXqpTboYge93ACdlVVY491QRd5gB5rXo+M z+BLiNLxqgQmBq81fCsuRTOKUnm3EgA0wJQidIcDFfGfc/zg5NzLewgbUfN28Dv94Dsg=; Received: from andrew by vps0.lunn.ch with local (Exim 4.94.2) (envelope-from ) id 1uoOoN-005D7L-1y; Tue, 19 Aug 2025 18:03:47 +0200 Date: Tue, 19 Aug 2025 18:03:47 +0200 From: Andrew Lunn To: Dongjin Kim Cc: Rob Herring , Krzysztof Kozlowski , Heiko Stuebner , devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] arm64: dts: rockchip: Change ethernet TXD timing delay value Message-ID: <4d25c642-d457-4cb7-8bc1-587edd4f1d75@lunn.ch> References: <20250819045018.2094282-1-tobetter@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20250819045018.2094282-1-tobetter@gmail.com> On Tue, Aug 19, 2025 at 01:50:17PM +0900, Dongjin Kim wrote: > Very poor network performance is observed on the ODROID-M1 Board > (REV 1.0 20220613) when running iperf3 (under 200Mbits/sec), and > this problem can be resolved after changing the value of TXD > timing to 0x35 from 0x4f. How did you decide on 0x35? ~/linux/arch/arm64$ grep -hr "tx_delay = " | sort | uniq -c 4 tx_delay = <0x10>; 1 tx_delay = <0x1a>; 1 tx_delay = <0x21>; 2 tx_delay = <0x22>; 4 tx_delay = <0x24>; 2 tx_delay = <0x26>; 14 tx_delay = <0x28>; 1 tx_delay = <0x2a>; 6 tx_delay = <0x30>; 1 tx_delay = <0x3a>; 3 tx_delay = <0x3c>; 2 tx_delay = <0x42>; 5 tx_delay = <0x43>; 2 tx_delay = <0x44>; 1 tx_delay = <0x46>; 6 tx_delay = <0x4f>; The numbers are all over the place, but it is clear that 0x28 is the most popular for some reason. But since this delay values are magic, i've no idea why. Andrew