From owner-freebsd-stable@FreeBSD.ORG Sun Feb 1 22:40:46 2009 Return-Path: Delivered-To: freebsd-stable@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 3D80A106567C for ; Sun, 1 Feb 2009 22:40:46 +0000 (UTC) (envelope-from borjamar@sarenet.es) Received: from proxypop2.sarenet.es (proxypop2.sarenet.es [194.30.0.95]) by mx1.freebsd.org (Postfix) with ESMTP id EAE798FC1D for ; Sun, 1 Feb 2009 22:40:45 +0000 (UTC) (envelope-from borjamar@sarenet.es) Received: from [127.0.0.1] (matahari.sarenet.es [192.148.167.18]) by proxypop2.sarenet.es (Postfix) with ESMTP id 22902731BA; Sun, 1 Feb 2009 23:40:44 +0100 (CET) Message-Id: <2C4CD129-43B3-49FA-8208-FAC25191D2F2@sarenet.es> From: Borja Marcos To: Robert Watson In-Reply-To: Content-Type: text/plain; charset=US-ASCII; format=flowed; delsp=yes Content-Transfer-Encoding: 7bit Mime-Version: 1.0 (Apple Message framework v930.3) Date: Sun, 1 Feb 2009 23:40:42 +0100 References: X-Mailer: Apple Mail (2.930.3) Cc: freebsd-stable@freebsd.org Subject: Re: Puzzling change in performance X-BeenThere: freebsd-stable@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Production branch of FreeBSD source code List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 01 Feb 2009 22:40:46 -0000 On Jan 31, 2009, at 7:27 PM, Robert Watson wrote: > There are basically three ways to go about exploring this, none > particularly good: > > (1) Do a more formal before and after analysis of performance on the > box, > perhaps using tools like kernel profiling, hwpmc, dtrace, etc. Machine in production, I cannot do it :( > (2) Do a binary search to narrow down the date of the change that > improved > things until it becomes clear which mattered. > (3) Hope someone annecdotally remembers something that might or > might not be > it and assume they're right. > > Of these, I'd guess (2) is actually the most effective way to go > about it, but is potentially time-consuming. As you point out, the > most interesting question is whether, when you go back to 7.0, > things suddenly get slower again, or not. Typically long uptimes > don't lead to performance problems on FreeBSD (in my experience) so > I think that's unlikely to be the source. There are a lot of > improvements in 7.1 relating to performance, but none particularly > stands out for me as having the effect you describe. If you're > really curious, I would try to pin it down with a binary search. I will have to learn how to use dtrace, I think. This is quite weird. And in a lot of years I haven't seen a FreeBSD system degraded because of a long uptime. Something in userland must be the culprit... As I see (I don't administer the machine but co-administer it) there's a Qmail system with some AV crap... and now I see that active memory had gone up, and is much lower after the update. I'll keep investigating.. the kind of answer I was looking for was a "oh, yes, there was a problem that degraded, blah, blah, blah". The graphs can be accessed here: http://194.30.110.21/orca/ It's behind an ADSL, so expect slow performance. Borja.