From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D5C3CC4361B for ; Thu, 17 Dec 2020 17:57:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9F02C238EF for ; Thu, 17 Dec 2020 17:57:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728000AbgLQR5P (ORCPT ); Thu, 17 Dec 2020 12:57:15 -0500 Received: from mail2.candelatech.com ([208.74.158.173]:34424 "EHLO mail3.candelatech.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727253AbgLQR5O (ORCPT ); Thu, 17 Dec 2020 12:57:14 -0500 Received: from [192.168.254.6] (unknown [50.46.158.169]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail3.candelatech.com (Postfix) with ESMTPSA id A6DCD13C2B3; Thu, 17 Dec 2020 09:56:33 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 mail3.candelatech.com A6DCD13C2B3 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=candelatech.com; s=default; t=1608227793; bh=Yb6clpUNehTgrSt4Z0khqCfulHBxDx2TKWifRk3QBIk=; h=Subject:To:Cc:References:From:Date:In-Reply-To:From; b=h+vdZszyJLHISoDgHs8jj4zu1jlyk8xWj6FfUkHiZJH+8MosuD3B5IpnnO8NACCrq drvtdbXYhxRaRgjJ563vl1mSCVaL/KRszNmVlv+K4s7CtVqBKs9uvuUQOiZkhgOFS8 salFh38HbjuvVnEfw0Te2kNJDXRW8FNXl8pVuFi8= Subject: Re: net: tso: add UDP segmentation support: adds regression for ax200 upload To: Eric Dumazet Cc: netdev References: <5664fa0f-aef2-c336-651a-093c9eed23ab@candelatech.com> <765f370d-ce2d-b75a-2dde-87f69ae7c185@candelatech.com> From: Ben Greear Organization: Candela Technologies Message-ID: Date: Thu, 17 Dec 2020 09:56:33 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-MW Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 12/17/20 2:11 AM, Eric Dumazet wrote: > On Thu, Dec 17, 2020 at 12:59 AM Ben Greear wrote: >> >> On 12/16/20 3:09 PM, Ben Greear wrote: >>> Hello Eric, >>> >>> The patch below evidently causes TCP throughput to be about 50Mbps instead of 700Mbps >>> when using ax200 to upload tcp traffic. >>> >>> When I disable TSO, performance goes back up to around 700Mbps. >> >> As a followup, when I revert the patch, upload speed goes to ~900Mbps, >> so even better than just disabling TSO (I left TSO enabled after reverting the patch). >> >> Thanks, >> Ben >> > > Thanks for the report ! > > It seems drivers/net/wireless/intel/iwlwifi/pcie/tx.c:iwl_fill_data_tbs_amsdu() > calls tso_build_hdr() with extra bytes (SNAP header), > it is not yet clear to me what is broken :/ Your patch is guessing tcp vs udp by looking at header length from what I could tell. So if something uses a different size, it probably gets confused? > > Can you confirm which driver is used for ax200 ? > > I see tso_build_hdr() also being used from > drivers/net/wireless/intel/iwlwifi/queue/tx.c I tested against the un-modified ax200 5.10.0 kernel driver, and it has the issue. The ax200 backports release/core56 driver acts a bit different (poorer performance over all than in-kernel driver), but has similar upstream issues that are mitigated by disabling TSO. Thanks, Ben -- Ben Greear Candela Technologies Inc http://www.candelatech.com