From owner-freebsd-net@freebsd.org Sun Jan 10 08:31:42 2016 Return-Path: Delivered-To: freebsd-net@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 907C8A694F8 for ; Sun, 10 Jan 2016 08:31:42 +0000 (UTC) (envelope-from sepherosa@gmail.com) Received: from mail-io0-x243.google.com (mail-io0-x243.google.com [IPv6:2607:f8b0:4001:c06::243]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 6368010AD for ; Sun, 10 Jan 2016 08:31:42 +0000 (UTC) (envelope-from sepherosa@gmail.com) Received: by mail-io0-x243.google.com with SMTP id q21so23857208iod.3 for ; Sun, 10 Jan 2016 00:31:42 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=+zYROqHmQiGAtCtBDMbYm5gXlJt0Fsit6vZ1IYu3yH8=; b=kFwrjtBsDuDdRyQevkKc0kIL0+6BScoeUw5tiuB4iur2u5dqRudEt7l9/eg+s2tprf Hn0sWty0MLhB5pviC3NhkXmlSa3Wf+CIKILC5WbAaIMyjbpQV+DW/j0Zqsbp27YtibJd 3icxhYNLLHiMiu9W9rMvEous6HpnFxWYjlZR+FYUuq31n2Emmzi1p8aATqNXfMMWjPlx EZQtvb4WqhvdDmT3/CWdBS8BEFwYliqvp9c5aGbZeFRe/VQ5Paz6BuIYDhpKWpQCEbAM 1lSXQnjk0nlz2ydoExWvhXMMjqq+00csr/3MpXg3tJ4KrQEZVAxhLDV9ewJD34W8Y0Ax AYdQ== MIME-Version: 1.0 X-Received: by 10.107.7.22 with SMTP id 22mr55221875ioh.17.1452414701960; Sun, 10 Jan 2016 00:31:41 -0800 (PST) Received: by 10.107.166.3 with HTTP; Sun, 10 Jan 2016 00:31:41 -0800 (PST) In-Reply-To: References: Date: Sun, 10 Jan 2016 16:31:41 +0800 Message-ID: Subject: Re: [Differential] [Request, 6 lines] D4825: tcp/lro: Add network driver configurable LRO entry depth From: Sepherosa Ziehau To: Ravi Pokala Cc: "freebsd-net@freebsd.org" Content-Type: text/plain; charset=UTF-8 X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 10 Jan 2016 08:31:42 -0000 On Fri, Jan 8, 2016 at 11:59 PM, Ravi Pokala wrote: > -----Original Message----- > > >>Date: Fri, 8 Jan 2016 02:29:22 +0000 >>From: "sepherosa_gmail.com (Sepherosa Ziehau)" >> >>To: freebsd-net@freebsd.org >>Subject: [Differential] [Request, 6 lines] D4825: tcp/lro: Add network >> driver configurable LRO entry depth >>Message-ID: >> >>Content-Type: text/plain; charset="utf-8" >> >>sepherosa_gmail.com created this revision. >>sepherosa_gmail.com added reviewers: network, adrian, delphij, decui_microsoft.com, honzhan_microsoft.com, howard0su_gmail.com, glebius. >>sepherosa_gmail.com added a subscriber: freebsd-net-list. >>Herald added a reviewer: transport. >> >>REVISION SUMMARY >> When there is only tiny amount of TCP connections and the host is slow, e.g. in VM, holding too much TCP segments in an LRO entry will cause RX performance degradation. We now allow network drivers to configure how deep one LRO entry should be. > > Forgive me if I'm missing something obvious, but this patch doesn't actually change anything - rather than hard-coding 65535, you're using lc->lro_hiwat... which is hard-coded to 65535. > > Right? The value is intended to be changed by NIC drivers, see the code commented out by the HN_LRO_HIWAT here: https://reviews.freebsd.org/D4824 Thanks, sephe