From owner-freebsd-stable@FreeBSD.ORG Mon May 9 17:07:19 2005 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id D103C16A4E9 for ; Mon, 9 May 2005 17:07:19 +0000 (GMT) Received: from pooker.samsco.org (pooker.samsco.org [168.103.85.57]) by mx1.FreeBSD.org (Postfix) with ESMTP id 4A2D143D79 for ; Mon, 9 May 2005 17:07:19 +0000 (GMT) (envelope-from scottl@samsco.org) Received: from [192.168.254.21] (rat.samsco.home [192.168.254.21]) (authenticated bits=0) by pooker.samsco.org (8.13.3/8.13.3) with ESMTP id j49HCFYf029357; Mon, 9 May 2005 11:12:15 -0600 (MDT) (envelope-from scottl@samsco.org) Message-ID: <427F9890.7010104@samsco.org> Date: Mon, 09 May 2005 11:06:24 -0600 From: Scott Long User-Agent: Mozilla/5.0 (X11; U; FreeBSD amd64; en-US; rv:1.7.5) Gecko/20050321 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Ewan Todd References: <20050509150018.GF281@mathcode.net> <427F8076.7030105@samsco.org> <20050509170316.GG281@mathcode.net> In-Reply-To: <20050509170316.GG281@mathcode.net> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-2.8 required=3.8 tests=ALL_TRUSTED autolearn=failed version=3.0.2 X-Spam-Checker-Version: SpamAssassin 3.0.2 (2004-11-16) on pooker.samsco.org cc: freebsd-stable Subject: Re: Performance issue X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 09 May 2005 17:07:19 -0000 Ewan Todd wrote: >>>Whereas, the typical result for the new rig looked more like >>> >>> 105.36 real 71.10 user 33.41 sys >>> ... >>> 10548 involuntary context switches >>> >>> >> >>First of all, make sure that you have WITNESS and INVARIANTS off in your >>kernel. You might also want to recompile your kernel with the SMP >>option turned off. >> >>Scott > > > First of all, thanks to Mike Tancsa for suggesting 5.4 RC4 and to Pete > French for running the test independently on the higher spec machines > with 5.4 RC4 on them, confirming the system time thing, ruling out an > AMD problem, dissociating the system time result from the context > switching, and saving me the trouble of rediscovering the same problem > on 5.4 RC4. > > This is my first foray into the public world of FreeBSD discussion > lists, and I am encouraged by the helpfulness of the response. > > Scott, the 5.3 kernel I had was a essentially a GENERIC release > kernel, with about 100 options commented out. WITNESS and INVARIANTS > are off by default, which I confirmed by looking through `sysctl -a`. > However, I was curious to see what I would get if I switched them on, > so I added these options and recompiled the kernel: > > options KDB > options DDB > options INVARIANTS > options INVARIANT_SUPPORT > options WITNESS > options WITNESS_SKIPSPIN > > The result, below, has essentially the same user time (or just less, > if that makes any sense), but tripled system time. The context > switches are consistent with the one-per-10msec I saw before. Is > there anything useful I can do while I still have the kernel debug > options on? > > -e > > > 172.29 real 67.53 user 103.07 sys > 23376 maximum resident set size > 659 average shared memory size > 20805 average unshared data size > 127 average unshared stack size > 5402 page reclaims > 0 page faults > 0 swaps > 0 block input operations > 0 block output operations > 0 messages sent > 0 messages received > 0 signals received > 0 voluntary context switches > 17234 involuntary context switches > > 5.3 ships with SMP turned on, which makes lock operations rather expensive on single-processor machines. 4.x does not have SMP turned on by default. Would you be able to re-run your test with SMP turned off? Scott