From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 8940F38838F; Fri, 9 Oct 2026 16:47:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791564457; cv=none; b=LUtb16vFUv6s/HkkLBOGTN1wzUx62bptNxSgXm4aC6A3k6tYu+An8rADaEutmjlxxA1fhnFOOTGpID6zJMx2xOxW7PoKf2mZMjytb+C0K50RDe7xv8jushj1tYcnI/DOFarIWdcJ4XdCR+JWYkCBq4km36E5kD5ONPBNOTTBDEk= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791564457; c=relaxed/simple; bh=s5cEuLdlN+PPlUwWQ58v32ncF+mLLnHpBX7/MXR94xw=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=eWWqSjeqc4rt3Y3GJ+l4Qlhmdw/F5bSyXll9/FquBzKSyXhQCFHtpBaOtusUpA3/g86o8aYYbZiIl+sky/SlYYh1uZkBuLptVJdAN/5UFIaw8e/Oezf+/pck1cltJZQclHAFYur+ocAbrE2IeIttDqy4ZS9hmllKMDv2Wic5rqE= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=R9R1Lm9s; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="R9R1Lm9s" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 7D2D01F000FF; Fri, 9 Oct 2026 16:47:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791564456; bh=0ZIVHrCq1ew1FhPHwVQ9oRt+nrgfNIPMv41G3Ez5E8E=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=R9R1Lm9suYUdjdSJxedpskqK6Qp7LUiKN6/eWE+TKp9Gyq7W4VE54LjMdYqXDt48Q DI+t26WB+/NsZBF+RAZF574+LbR6ha78Hl+n2NW6sEa9wqcVC3/MfFa9tvIvqpYqys QxEVh3y+Mq+wLV1/mBiaHkHfEZQxvS6fTGZMZD67fIsjAk8T28Qasdk8JvR/4vuuSf M8X3QhvWiTygJlbqbqpWebiyp+PMd4qdV/R9zOzTMaN+dmUzXle00yfFjqAD5wCvbV VF1HXxChauwkK5NMXA8J22dQes3AvdKlB0xYT69W+N6Ic90NwCqs54hsI0+4JZKJon 9BYN1S/90wexw== Date: Fri, 9 Oct 2026 17:47:32 +0100 From: Simon Horman To: Rosen Penev Cc: netdev@vger.kernel.org, Chris Snook , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , open list Subject: Re: [PATCH net-next] net: ag71xx: align the IP header behind DSA tags Message-ID: <20261009164732.GG83879@horms.kernel.org> References: <20261007174449.671416-1-rosenp@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: <20261007174449.671416-1-rosenp@gmail.com> On Wed, Oct 07, 2026 at 10:44:49AM -0700, Rosen Penev wrote: > The receive buffer offset includes NET_IP_ALIGN to get the IP header > aligned behind a 14 byte Ethernet header. Most ag71xx devices use DSA > switches whose tag sits in front of the EtherType, which moves the IP > header by another 2 bytes. Every access to the IP and TCP headers then > traps and gets emulated by the unaligned access handler, around 6 times > per forwarded frame. > > Take the headroom needed by the DSA tagger into account when choosing > the offset. > > TP-Link Archer C7 v2 (qca8k), median of 3 runs, Mbit/s: > > before after > routed up 743 855 > routed down 660 749 > local receive 554 572 > > The unaligned instruction counter no longer moves while forwarding. > > Assisted-by: LLM > Signed-off-by: Rosen Penev Unfortunately this patch did not apply cleanly to net-next at the time it was posted, so our CI did not run. Please rebase and repost. -- pw-bot: changes-requested