From owner-svn-src-head@freebsd.org  Tue Jan 26 22:44:41 2016
Return-Path: <owner-svn-src-head@freebsd.org>
Delivered-To: svn-src-head@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 62C5CA6E57E;
 Tue, 26 Jan 2016 22:44:41 +0000 (UTC)
 (envelope-from glebius@FreeBSD.org)
Received: from cell.glebi.us (glebi.us [96.95.210.25])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
 (Client CN "cell.glebi.us", Issuer "cell.glebi.us" (not verified))
 by mx1.freebsd.org (Postfix) with ESMTPS id 4EF4B1442;
 Tue, 26 Jan 2016 22:44:40 +0000 (UTC)
 (envelope-from glebius@FreeBSD.org)
Received: from cell.glebi.us (localhost [127.0.0.1])
 by cell.glebi.us (8.15.2/8.15.2) with ESMTPS id u0QMidvs015682
 (version=TLSv1.2 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO);
 Tue, 26 Jan 2016 14:44:39 -0800 (PST)
 (envelope-from glebius@FreeBSD.org)
Received: (from glebius@localhost)
 by cell.glebi.us (8.15.2/8.15.2/Submit) id u0QMidUJ015681;
 Tue, 26 Jan 2016 14:44:39 -0800 (PST)
 (envelope-from glebius@FreeBSD.org)
X-Authentication-Warning: cell.glebi.us: glebius set sender to
 glebius@FreeBSD.org using -f
Date: Tue, 26 Jan 2016 14:44:39 -0800
From: Gleb Smirnoff <glebius@FreeBSD.org>
To: Sepherosa Ziehau <sephe@FreeBSD.org>, adrian@FreeBSD.org
Cc: src-committers@freebsd.org, svn-src-all@freebsd.org,
 svn-src-head@freebsd.org
Subject: Re: svn commit: r294788 - head/sys/dev/hyperv/netvsc
Message-ID: <20160126224439.GT6885@FreeBSD.org>
References: <201601260942.u0Q9gD14062309@repo.freebsd.org>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <201601260942.u0Q9gD14062309@repo.freebsd.org>
User-Agent: Mutt/1.5.24 (2015-08-30)
X-BeenThere: svn-src-head@freebsd.org
X-Mailman-Version: 2.1.20
Precedence: list
List-Id: SVN commit messages for the src tree for head/-current
 <svn-src-head.freebsd.org>
List-Unsubscribe: <https://lists.freebsd.org/mailman/options/svn-src-head>,
 <mailto:svn-src-head-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/svn-src-head/>
List-Post: <mailto:svn-src-head@freebsd.org>
List-Help: <mailto:svn-src-head-request@freebsd.org?subject=help>
List-Subscribe: <https://lists.freebsd.org/mailman/listinfo/svn-src-head>,
 <mailto:svn-src-head-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 26 Jan 2016 22:44:41 -0000

  Sepherosa,

On Tue, Jan 26, 2016 at 09:42:13AM +0000, Sepherosa Ziehau wrote:
S> Author: sephe
S> Date: Tue Jan 26 09:42:13 2016
S> New Revision: 294788
S> URL: https://svnweb.freebsd.org/changeset/base/294788
S> 
S> Log:
S>   hyperv/hn: Improve sending performance
S>   
S>   - Avoid main lock contention by trylock for if_start, if that fails,
S>     schedule TX taskqueue for if_start
S>   - Don't do direct sending if the packet to be sent is large, e.g.
S>     TSO packet.
S>   
S>   This change gives me stable 9.1Gbps TCP sending performance w/ TSO
S>   over a 10Gbe directly connected network (the performance fluctuated
S>   between 4Gbps and 9Gbps before this commit). It also improves non-
S>   TSO TCP sending performance a lot.
S>   
S>   Reviewed by:		adrian, royger
S>   Approved by:		adrian (mentor)
S>   Sponsored by:		Microsoft OSTC
S>   Differential Revision:	https://reviews.freebsd.org/D5074

Why do you actually use if_start, not if_transmit?

-- 
Totus tuus, Glebius.