From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 499D43D4133; Mon, 2 Mar 2026 14:02:19 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772460139; cv=none; b=i/tzEE2NPYWcG5OJSq1MXTyMifVG3ScWqXe46S5bdn2qROvgFEzwnUWAn6mpOCs1efjJGVPmD6kGvFbgj7h1sABa2coYHXA7/WCqyjA+XwzKoqqeszM8KwSfUsx1vCcwnhe51syzHETez+El/Edi9xtqRC9z+zZ+bd/K16kyZx8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1772460139; c=relaxed/simple; bh=vS7JKHydz7PX7gecBPBnpNdobodFV4i0rWhwWuR0+7I=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=C8tyQjlF1M4EmdwgB9vs2H2LwpqQA/7PtThazEfD6ugQogy2BbQSdyUP+FXyUVfrBY3ghVlHqd8xF2Tr5QDmbZo01sJpaguSiVA2FzCI5IX4yutZPFVSjtlUJnt6worot0ntAhRQJb60VfnznIb0BUU/r2n6KFVcN4EPLBg/7Uc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=T9hY9JNG; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="T9hY9JNG" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 2966BC19423; Mon, 2 Mar 2026 14:02:13 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1772460139; bh=vS7JKHydz7PX7gecBPBnpNdobodFV4i0rWhwWuR0+7I=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=T9hY9JNGCjpkeiHDRUeo95vcKHBVptO7U/4bPCLFbsrsa+cRjITbyIiD5DaKiq/p2 P0xZk6qcxMAd8kebSEFQN8VL48BDN1Q5b3MR+SL9+QvtHYSzuKX9+UlDFrDhvAZfv4 flRiymWam0e/Iy0KDg9S7Cc/6TC10BXo8MQaJJon645Zd8PMXZVvkd2axIJnhodC11 TNtucIc6RAkaUzRlEdmCFLzZyje3S7IwtL8bRqsqAQwHJzx5oVfc2XiNv4VpfnkXe+ BOGybke+gWc22aqvKS9PyZsOAK4ZJX9UVrC5bdUWYlIXVKlgIX/3/Nu1gbWREM0doU i45+wv5xrNrBQ== Date: Mon, 2 Mar 2026 14:02:11 +0000 From: Simon Horman To: Dipayaan Roy Cc: kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org, decui@microsoft.com, andrew+netdev@lunn.ch, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, leon@kernel.org, longli@microsoft.com, kotaranov@microsoft.com, shradhagupta@linux.microsoft.com, ssengar@linux.microsoft.com, ernis@linux.microsoft.com, shirazsaleem@microsoft.com, linux-hyperv@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, dipayanroy@microsoft.com Subject: Re: [PATCH net-next] net: mana: Force full-page RX buffers for 4K page size on specific systems. Message-ID: References: Precedence: bulk X-Mailing-List: netdev@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: On Fri, Feb 27, 2026 at 02:15:12AM -0800, Dipayaan Roy wrote: > On certain systems configured with 4K PAGE_SIZE, utilizing page_pool > fragments for RX buffers results in a significant throughput regression. > Profiling reveals that this regression correlates with high overhead in the > fragment allocation and reference counting paths on these specific > platforms, rendering the multi-buffer-per-page strategy counterproductive. > > To mitigate this, bypass the page_pool fragment path and force a single RX > packet per page allocation when all the following conditions are met: > 1. The system is configured with a 4K PAGE_SIZE. > 2. A processor-specific quirk is detected via SMBIOS Type 4 data. > > This approach restores expected line-rate performance by ensuring > predictable RX refill behavior on affected hardware. > > There is no behavioral change for systems using larger page sizes > (16K/64K), or platforms where this processor-specific quirk do not > apply. > > Signed-off-by: Dipayaan Roy Reviewed-by: Simon Horman