From owner-freebsd-stable@FreeBSD.ORG Mon May 9 17:03:14 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 E0C1E16A4E9 for ; Mon, 9 May 2005 17:03:14 +0000 (GMT) Received: from ylpvm12.prodigy.net (ylpvm12-ext.prodigy.net [207.115.57.43]) by mx1.FreeBSD.org (Postfix) with ESMTP id E04A443D3F for ; Mon, 9 May 2005 17:03:12 +0000 (GMT) (envelope-from ewan@mathcode.net) Received: from pimout1-ext.prodigy.net (pimout1-ext.prodigy.net [207.115.63.77])j49H3Aee014683 for ; Mon, 9 May 2005 13:03:10 -0400 X-ORBL: [68.23.218.132] Received: from mail.mathcode.net (adsl-68-23-218-132.dsl.wotnoh.ameritech.net [68.23.218.132])j49H349Z169436; Mon, 9 May 2005 13:03:11 -0400 Received: from bsd.mathcode.net (localhost [127.0.0.1]) by mail.mathcode.net (8.12.11/8.12.11) with ESMTP id j49H3JKs010008; Mon, 9 May 2005 13:03:19 -0400 (EDT) (envelope-from ewan@bsd.mathcode.net) Received: (from ewan@localhost) by bsd.mathcode.net (8.12.11/8.12.11/Submit) id j49H3Gj9010007; Mon, 9 May 2005 13:03:16 -0400 (EDT) (envelope-from ewan) Date: Mon, 9 May 2005 13:03:16 -0400 From: Ewan Todd To: Scott Long Message-ID: <20050509170316.GG281@mathcode.net> References: <20050509150018.GF281@mathcode.net> <427F8076.7030105@samsco.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <427F8076.7030105@samsco.org> User-Agent: Mutt/1.4.2.1i X-Spam-Status: No, hits=0.0 required=5.0 tests=none autolearn=no version=2.64 X-Spam-Checker-Version: SpamAssassin 2.64 (2004-01-11) on bsd.mathcode.net 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 17:03:15 -0000 > > > >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