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 963FF1AD48B for ; Thu, 20 Jun 2024 13:45:48 +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=1718891148; cv=none; b=J+lODC+otrzIDLTSNdz8Z5UqAX51SoyOwMHDreJ6IimFfAOdcB+3OMnnxRrxgYiJQeQ1vuuczJA1VFOPEPX0TQpMEb1jFesybTMY+Wj0fWLiFwBRqK7Jrvt/Dt7Wly7xWf9S+SG16IICGrvdl78pzYb3DQXYj+uidSjpGp1Z0ms= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718891148; c=relaxed/simple; bh=LjnbhWXQYul63vQ+DA6xjJXGdgliS0uVuqTNFFWWNxI=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=QEHHbTh8rATfpqWbtllYeJUlqfSoGdD3zm+sBSTMK9NLvkynWWco2McwJURto6sQR3OPLKfQWUwTEzj5HeGWiIxIEa9fRwSEGn9nci3cywwbSW1RIcbEyMDs9WwJuMH0pxcEOMX8oTgY1krGviZeZhxpW1/2SKvkdH05lUVRwNs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Mo6Dlw03; 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="Mo6Dlw03" Received: by smtp.kernel.org (Postfix) with ESMTPSA id BBABEC2BD10; Thu, 20 Jun 2024 13:45:47 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1718891148; bh=LjnbhWXQYul63vQ+DA6xjJXGdgliS0uVuqTNFFWWNxI=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=Mo6Dlw032lqISVnxlyhmZqrC7NqD+bq/ACOrsTuZRMParpx4183OTaAMsRi0aS/uT 60QxwlPBgo0zR6AevOkgzmaPDoFTYfvf8ANE7/zJFM5Z6l3CBRHWeRVete4xMMcWAa +yb6oElw5pVA6TdY7KLZ/Wu7J7thVrX9GEatL1x20tUexQZrJwfP3LqsFnyO+1HSZV WIaKr+fPHrWFkyOIE82I15SFSu2RY68ZCCIMFhLY4gOaw3MGb2dhxG8aPvcpQNLfQj dT7oNEh9b92vXVNub6fO7YvsBhbQASzpM5t7NmK+fhHsh4fSCrm3vjup5CGFUzI8WQ pLaKCIi9E+4yQ== Date: Thu, 20 Jun 2024 06:45:46 -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: <20240620064546.16b0019e@kernel.org> In-Reply-To: References: <20240618215313.29631-1-michael.chan@broadcom.com> <20240618215313.29631-3-michael.chan@broadcom.com> <20240619171301.6fefef59@kernel.org> 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 Wed, 19 Jun 2024 23:50:42 -0700 Michael Chan wrote: > > 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. > > This issue only affects the newest chip which just started production > and the production FW has this updated interface. Hm, okay, I see this only needs to go back to 6.8. > > 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. > > That's true for Big TCP, but what about UDP GSO? Can UDP GSO exceed > 2k segments? I really don't think 2k segment limit is of any practical concern. What I have seen for UDP GSO, since its used mostly for QUIC and mostly on edge / in CDN - the speeds are much lower, so the QUIC stacks only use sends of 16k or so. Anyway, the "this is only needed in 6.8" convinced me, I'll apply.