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 Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 8B69EC4332F for ; Wed, 16 Nov 2022 03:00:20 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ov8e2-0003yo-Cj; Tue, 15 Nov 2022 21:59:22 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1ov8e0-0003yX-7n; Tue, 15 Nov 2022 21:59:21 -0500 Received: from mail.aperture-labs.org ([195.191.197.3]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_CHACHA20_POLY1305:256) (Exim 4.90_1) (envelope-from ) id 1ov8dx-0002K7-D2; Tue, 15 Nov 2022 21:59:19 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fiebig.nl; s=key01; t=1668567537; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=gnQPo5C4Uy3g049zDmvGKrEqbIHMwh7mCZYuYhvz5fQ=; b=FGrAyprBCduf6F5WbN6lrFi8SQ5mWbCfhofHpOi3x1waU8fbEOZRBjcsb/pUgH/HB8Fn25 rxoWBL7KyZCBdKTQ466gPliVQ7cHNpAIeuMC/ot4EzEcUJx/C+geJ7hBQFZGAJhY+5i8sE nPV/rSlAQ9NamPNNv7mzs078jhW29jXWTJmaWHUJFV37IidphZ7g3tDJAsHmY1IVGAl8gs 5gImd48+vTOdcWa9fh/6R6l45PN4eyihlXX5acTfpHSG53Ix3lg0VpY/OZXg7fOdf0AV05 Ik7wHt+WwIYpl6KjKB7hOew8/wqS6TNkzF0orjz6qsuJ23W7pYC0yjOWR2XnfA== Received: from DESKTOP1J9BJ88 ( [2a06:d1c1:a:0:d0f7:15f4:7842:c716]) by mail.aperture-labs.org (OpenSMTPD) with ESMTPSA id a126268a (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256:NO); Wed, 16 Nov 2022 02:58:57 +0000 (UTC) From: "Tobias Fiebig" To: "'Stefan Hajnoczi'" , Cc: , , "'Russell King - ARM Linux'" References: <20221115163659.1595865-1-stefanha@redhat.com> In-Reply-To: Subject: RE: [PATCH for-7.2] rtl8139: honor large send MSS value Date: Wed, 16 Nov 2022 03:58:54 +0100 Message-ID: <011801d8f967$5dad0f00$19072d00$@fiebig.nl> MIME-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable X-Mailer: Microsoft Outlook 16.0 Thread-Index: AQIsokZAyfqueh54+bOmp3YoqNF9QAJffM5ArYaKxRA= Content-Language: en-nl Received-SPF: pass client-ip=195.191.197.3; envelope-from=tobias@fiebig.nl; helo=mail.aperture-labs.org X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Heho, I just tested around with the patch; Good news: Certainly my builds are being executed. Also, if I patch the = old code to have a MAX_MTU <=3D the max MTU on my path, throughput is = ok. Bad news: Something is wrong with getting the MSS in the patch you = shared. When enabling DPRINT, values are off (sent MSS vs. printed MSS): 600 2060 800 2308 1000 2316 1023 2307 1200 3076 1400 3340 (most likely clamped to 1320) Fiddling around a bit more, I found txdw0 printed earlier in the stack = as hex (sent MSS, txdw0): 769 900502f5 1000 900503dc 1280 900504f4 1281 900504f5 1301 90050509 1317 90050519 1320 9005051c This maps rather well to: MSS =3D txdw0 - 2416246772=20 MSS =3D txdw0 - 9004FFF4 Sadly, my C is 'non-existent' and it is kind-of 4AM, so also not in the = brainspace to fill those gaps. But if one of you could look at the patch = again, that would be nice. Otherwise, I should have some brainspace for = this tomorrow night (UTC) again. With best regards, Tobias