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 B2043C433FE for ; Thu, 17 Nov 2022 16:56:24 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1oviBO-0005oG-CH; Thu, 17 Nov 2022 11:56:10 -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 1oviBK-0005nR-Jx for qemu-devel@nongnu.org; Thu, 17 Nov 2022 11:56:06 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1oviBI-0007kx-UK for qemu-devel@nongnu.org; Thu, 17 Nov 2022 11:56:06 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1668704163; 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; bh=nP5m9L17G85QMMIi9xZRbcIh20uXHffvhLnPwT5Mh18=; b=D8SxX1jUrjLVeveaGIKksRDBgFyByQfmxn4TDlnRdWuwmyVLbpn+PHmwC4NgsK/dt9W8xI wjhFPf4TQV7FiWNzvbDbxm1/f68v4Hwptd5myboFfPkdngbI+VGBLCiTqg0RpT5DsKqJMV 2BkSLOjOanhn+Aqg8+WXryFJR31wNPs= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-424-CAtRjoOQPZO2RBbLxNee5A-1; Thu, 17 Nov 2022 11:55:59 -0500 X-MC-Unique: CAtRjoOQPZO2RBbLxNee5A-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.rdu2.redhat.com [10.11.54.2]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 1BD823C11EA2; Thu, 17 Nov 2022 16:55:59 +0000 (UTC) Received: from localhost (unknown [10.39.193.61]) by smtp.corp.redhat.com (Postfix) with ESMTP id 5A73E40C6EC3; Thu, 17 Nov 2022 16:55:58 +0000 (UTC) From: Stefan Hajnoczi To: qemu-devel@nongnu.org Cc: Tobias Fiebig , Jason Wang , qemu-stable@nongnu.org, Stefan Hajnoczi Subject: [PATCH for-7.2 v3 0/3] rtl8139: honor large send MSS value Date: Thu, 17 Nov 2022 11:55:51 -0500 Message-Id: <20221117165554.1773409-1-stefanha@redhat.com> Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Scanned-By: MIMEDefang 3.1 on 10.11.54.2 Received-SPF: pass client-ip=170.10.133.124; envelope-from=stefanha@redhat.com; helo=us-smtp-delivery-124.mimecast.com 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, DKIMWL_WL_HIGH=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.001, SPF_HELO_NONE=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 v3: - Add Patch 1 to avoid clobbering tx descriptor bits - Add Patch 2 to avoid confusing tx command modes - Exclude IP and TCP headers from large send MSS value The rtl8139 large send offload currently does not honor the MSS value provided by the driver. This is a problem especially when the MTU is small because IP fragmentation occurs and leads to poor performance. These patches make use of the large send MSS value. I have done basic testing by running the following Python code inside the guest: import socket s = socket.socket() s.connect(('10.0.2.2', 1234)) buf = b'A' * 4096 s.send(buf) The device sees a 4150 byte tx descriptor that results in the transmission of 3 Ethernet frames with sizes of 1514, 1514, and 1230 bytes when the large send MSS value is 1460 bytes. Stefan Hajnoczi (3): rtl8139: avoid clobbering tx descriptor bits rtl8139: keep Tx command mode 0 and 1 separate rtl8139: honor large send MSS value hw/net/rtl8139.c | 47 ++++++++++++++++++++++++----------------------- 1 file changed, 24 insertions(+), 23 deletions(-) -- 2.38.1