From owner-freebsd-net@freebsd.org Sun Jan 10 08:32:18 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 C2976A6954D for ; Sun, 10 Jan 2016 08:32:18 +0000 (UTC) (envelope-from sepherosa@gmail.com) Received: from mail-ig0-x244.google.com (mail-ig0-x244.google.com [IPv6:2607:f8b0:4001:c05::244]) (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 950B111A2 for ; Sun, 10 Jan 2016 08:32:18 +0000 (UTC) (envelope-from sepherosa@gmail.com) Received: by mail-ig0-x244.google.com with SMTP id y8so11039014igw.0 for ; Sun, 10 Jan 2016 00:32:18 -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=QGH7K8Ff8Mtj7yVki1NAJEFzZDw0+WVjEY9QxibIOsc=; b=ympcUBm2OgrO01zgKqQaH4G3jT020H+wS/377lAR2pPyrninixDBy5ZyxWpOzxRtUj CWSJDtCTIdsrJLnE+UIQCdsJor1uRty2B9GJU1lDLwSEJIlqz7OxkombeehSXCBFFVvH +bWpgpI8GS+CyoX4/GhmxzwRDcUEI1o7nEtceVjW/loBLoLf1QBHkjoVQ9kmtwanPKD5 uyc/cwSagkgIiPsFvpHdTZc52bu03xik5eHy9eT7dnLU3Ih51QTC0ga0CF4UFJtnhAo3 5MxEkgIyjQplzWHdby5E52P/sgGk7ZKZt4r4E3hsXBYa9S6gOHuE03HGPqDtWBmRlSev n6mw== MIME-Version: 1.0 X-Received: by 10.50.109.167 with SMTP id ht7mr7008523igb.38.1452414737871; Sun, 10 Jan 2016 00:32:17 -0800 (PST) Received: by 10.107.166.3 with HTTP; Sun, 10 Jan 2016 00:32:17 -0800 (PST) In-Reply-To: References: Date: Sun, 10 Jan 2016 16:32:17 +0800 Message-ID: Subject: Re: [Differential] [Request, 6 lines] D4825: tcp/lro: Add network driver configurable LRO entry depth From: Sepherosa Ziehau To: Adrian Chadd Cc: Ravi Pokala , "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 08:32:18 -0000 On Sat, Jan 9, 2016 at 1:03 AM, Adrian Chadd wrote: > On 8 January 2016 at 07:59, 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? >> > > Right; I'm assuming their driver will twiddle this appropriately over time. Yeah, by drivers, and through a driver sysctl