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 56B76365 for ; Thu, 20 Jun 2024 00:13:03 +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=1718842383; cv=none; b=OQr2MPnaVUt0YlDVvnSzgK3EhP5Q4pf/Tv97Ejh2Sy2ngfe0hhOGdQbHjqSHHn/eyJtCBMCj1dzvitAEZ3tFSf74rjxe2QV5iZVzKgrBm+mqeLMYXXGkS6SeIAJvkMPYkUIpuk1zxfSpFhlfyNR1OY0C4VdIAQ7Hcpi1peRW4rA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718842383; c=relaxed/simple; bh=cPsrnkKh+h7e5ODGDZsRFkE0TJGttYhgDdwirTlIk94=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=Xq8zk6ZKVqvBFEEUzdKtx5NXBkAlrjCbr/6CpFVCJT+AkLVHljoHz7KMTr8H66F/UTm6rlUHK0Sq4nsUuTNOb06zF4PiRfNNi9O31byprp3GskFUC3JOEJhdSf3kI/c7J5YEng8TtQXhUgHsX7zBhbq0Kzg1tHN1R4y50XmFYmU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=OHtafr7z; 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="OHtafr7z" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6DDC9C2BBFC; Thu, 20 Jun 2024 00:13:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1718842382; bh=cPsrnkKh+h7e5ODGDZsRFkE0TJGttYhgDdwirTlIk94=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=OHtafr7zzWnY/EpYA/DQuFCCa6pqx2qADNN5aYEcsXp1pGFILLiEByH3HtuG0bAze bfA9KWd1ykPlhhcGBHrDJyUbiUQnEiBheQAxdHhVwjvdDbVTZjvg0dWqZYGlIXKkGV PzJmJj9/PrvdWD0UGbfuhm+Sv9FLo8YEgGxuD8bN4PKz+JvnXo00P/iwcxHrozPap3 BBCw6prlMtyY42jpDwbsFCGAzIIm6pElxdfspLhZ1JLLdyuWFJEb9jKhQPeXH8W0i/ vp4TDWHCawlzRenkjQ7+CC0rmrNL5L/dLdc5f4OskzpDf42U8Busl2jVQHsUIh1aSh VJkhyVkmkbshA== Date: Wed, 19 Jun 2024 17:13:01 -0700 From: Jakub Kicinski To: Michael Chan Cc: davem@davemloft.net, netdev@vger.kernel.org, edumazet@google.com, pabeni@redhat.com, pavan.chebbi@broadcom.com, andrew.gospodarek@broadcom.com, Ajit Khaparde , Somnath Kotur Subject: Re: [PATCH net 2/3] bnxt_en: Set TSO max segs on devices with limits Message-ID: <20240619171301.6fefef59@kernel.org> In-Reply-To: <20240618215313.29631-3-michael.chan@broadcom.com> References: <20240618215313.29631-1-michael.chan@broadcom.com> <20240618215313.29631-3-michael.chan@broadcom.com> 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-Transfer-Encoding: 7bit On Tue, 18 Jun 2024 14:53:12 -0700 Michael Chan wrote: > Firmware will now advertise a non-zero TSO max segments if the > device has a limit. 0 means no limit. The latest 5760X chip > (early revs) has a limit of 2047 that cannot be exceeded. If > exceeded, the chip will send out just a small number of segments. If we're only going to see 0 or 2047 pulling in the FW interface update and depending on newer FW version isn't a great way to fix this, IMHO. TCP has min MSS of 500+ bytes, so 2k segments gives us 1MB LSO at min legitimate segment size, right? So this is really just a protection against bugs in the TCP stack, letting MSS slide below 100. For a fix I'd just hardcode this to 2047 or even just 1k, and pull in the new FW interface to make it configurable in net-next. -- pw-bot: cr