From owner-freebsd-stable@FreeBSD.ORG  Fri Mar 20 23:12:44 2015
Return-Path: <owner-freebsd-stable@FreeBSD.ORG>
Delivered-To: freebsd-stable@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org
 [IPv6:2001:1900:2254:206a::19:1])
 (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by hub.freebsd.org (Postfix) with ESMTPS id 94EEB7CD;
 Fri, 20 Mar 2015 23:12:44 +0000 (UTC)
Received: from elsa.codelab.cz (elsa.codelab.cz [94.124.105.4])
 (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits))
 (Client did not present a certificate)
 by mx1.freebsd.org (Postfix) with ESMTPS id 4AA45B8E;
 Fri, 20 Mar 2015 23:12:42 +0000 (UTC)
Received: from elsa.codelab.cz (localhost [127.0.0.1])
 by elsa.codelab.cz (Postfix) with ESMTP id 361172842F;
 Sat, 21 Mar 2015 00:06:26 +0100 (CET)
Received: from illbsd.quip.test (ip-89-177-50-74.net.upcbroadband.cz
 [89.177.50.74])
 (using TLSv1 with cipher DHE-RSA-AES128-SHA (128/128 bits))
 (No client certificate requested)
 by elsa.codelab.cz (Postfix) with ESMTPSA id 0DE1A2842B;
 Sat, 21 Mar 2015 00:06:24 +0100 (CET)
Message-ID: <550CA812.8070509@quip.cz>
Date: Sat, 21 Mar 2015 00:06:58 +0100
From: Miroslav Lachman <000.fbsd@quip.cz>
User-Agent: Mozilla/5.0 (X11; FreeBSD amd64;
 rv:35.0) Gecko/20100101 Firefox/35.0 SeaMonkey/2.32
MIME-Version: 1.0
To: Mike Tancsa <mike@sentex.net>, John-Mark Gurney <jmg@funkthat.com>
Subject: Re: RELENG_10 performance regression (was Re: 35-40%
 performance drop releng9 vs releng10 openvpn
References: <5506250A.2000506@sentex.net>
 <20150316132055.GQ32288@funkthat.com> <5509D6C6.4050204@sentex.net>
 <20150318211457.GL51048@funkthat.com> <550B6950.8060806@sentex.net>
 <550C5AAF.9060502@sentex.net> <550C8AEE.4090408@sentex.net>
In-Reply-To: <550C8AEE.4090408@sentex.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed
Content-Transfer-Encoding: 7bit
Cc: FreeBSD-STABLE Mailing List <freebsd-stable@freebsd.org>,
 John Baldwin <jhb@freebsd.org>
X-BeenThere: freebsd-stable@freebsd.org
X-Mailman-Version: 2.1.18-1
Precedence: list
List-Id: Production branch of FreeBSD source code <freebsd-stable.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-stable>,
 <mailto:freebsd-stable-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-stable/>
List-Post: <mailto:freebsd-stable@freebsd.org>
List-Help: <mailto:freebsd-stable-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-stable>,
 <mailto:freebsd-stable-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Fri, 20 Mar 2015 23:12:44 -0000

Mike Tancsa wrote on 03/20/2015 22:02:
> OK, I think I found where the RELENG_10 performance loss happened. It seems
> https://lists.freebsd.org/pipermail/svn-src-stable-10/2015-March/004778.html
>
> is the issue.
>
> Testing with a kernel from r279796 I get 76-77Mb of throughput.  With
> r279848 it drops to about 60Mb

I am surprised by this huge performance drop.
If it is really caused by this change (VFS timestamp precision from 
seconds to microseconds), wasn't this change tested before commit?

Miroslav Lachman