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=-0.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 9C099C3A5A6 for ; Thu, 19 Sep 2019 12:33:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 7867821848 for ; Thu, 19 Sep 2019 12:33:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732110AbfISMdA (ORCPT ); Thu, 19 Sep 2019 08:33:00 -0400 Received: from shards.monkeyblade.net ([23.128.96.9]:55686 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727980AbfISMc7 (ORCPT ); Thu, 19 Sep 2019 08:32:59 -0400 Received: from localhost (unknown [86.58.254.34]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id 4DE2D154F7DB6; Thu, 19 Sep 2019 05:32:57 -0700 (PDT) Date: Thu, 19 Sep 2019 14:32:52 +0200 (CEST) Message-Id: <20190919.143252.1698401511955783402.davem@davemloft.net> To: gerlitz.or@gmail.com Cc: edumazet@google.com, netdev@vger.kernel.org, eric.dumazet@gmail.com, soheil@google.com, ncardwell@google.com, ycheng@google.com, daniel@iogearbox.net, tariqt@mellanox.com Subject: Re: [PATCH net-next] tcp: force a PSH flag on TSO packets From: David Miller In-Reply-To: References: <20190910214928.220727-1-edumazet@google.com> X-Mailer: Mew version 6.8 on Emacs 26.2 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Thu, 19 Sep 2019 05:32:59 -0700 (PDT) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Or Gerlitz Date: Thu, 19 Sep 2019 15:17:54 +0300 > On Wed, Sep 11, 2019 at 12:54 AM Eric Dumazet wrote: >> When tcp sends a TSO packet, adding a PSH flag on it >> reduces the sojourn time of GRO packet in GRO receivers. >> >> This is particularly the case under pressure, since RX queues >> receive packets for many concurrent flows. >> >> A sender can give a hint to GRO engines when it is >> appropriate to flush a super-packet, especially when pacing > > Hi Eric, > > Is this correct that we add here the push flag for the tcp header template > from which all the tcp headers for SW GSO packets will be generated? > > Wouldn't that cause a too early flush on GRO engines at the receiver side? I thought segmentation offload mechanism are not supposed to propagate the PSH to all of the packets.