From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pigeon.gentoo.org ([208.92.234.80] helo=lists.gentoo.org) by finch.gentoo.org with esmtp (Exim 4.60) (envelope-from <gentoo-user+bounces-109343-garchives=archives.gentoo.org@lists.gentoo.org>) id 1NvIMP-0002Xe-1p for garchives@archives.gentoo.org; Fri, 26 Mar 2010 22:50:37 +0000 Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id C5FA9E07BA; Fri, 26 Mar 2010 22:50:07 +0000 (UTC) Received: from mail-gy0-f181.google.com (mail-gy0-f181.google.com [209.85.160.181]) by pigeon.gentoo.org (Postfix) with ESMTP id A8E4DE07BA for <gentoo-user@lists.gentoo.org>; Fri, 26 Mar 2010 22:50:07 +0000 (UTC) Received: by gyh20 with SMTP id 20so4524010gyh.40 for <gentoo-user@lists.gentoo.org>; Fri, 26 Mar 2010 15:50:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:sender:received:in-reply-to :references:date:x-google-sender-auth:received:message-id:subject :from:to:content-type; bh=n00kquI36Sa5IDe9kKoEn2xiuAtVBoPEoU9aqBAAz5g=; b=h/NeNP7qneUZqAZtpUvlIhwpl3r05VGyc+7u8uDmQyCEPoFQmT8PhmLbLq1AZ3NMxJ s3WKpWJqqozsVAoEHLXqCOaEudH+kGWC2Hf0Q+MqVlEEMFvNzJsjfN73xaZMfhVv0Om+ 7Lp73Vct9P6G/7yMJU9ZJYzIXd709yx4kcc3o= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:content-type; b=ozh+BFv8NsdCw5QI1MrU0e+rojVQ+lqJ95CDf61b+9ScspslGOqH92tLhc/u+AjWca hIUiiTRk3aSfTnz/vLySN4at26CfI7CtmD1LOuZVt/jyq8q6xEQD/tbiWVN+Ay5z1qFI 1dQtK/HW4ArE4ZhhiAdkJcm6RKvhNEX9QQ+dc= Precedence: bulk List-Post: <mailto:gentoo-user@lists.gentoo.org> List-Help: <mailto:gentoo-user+help@lists.gentoo.org> List-Unsubscribe: <mailto:gentoo-user+unsubscribe@lists.gentoo.org> List-Subscribe: <mailto:gentoo-user+subscribe@lists.gentoo.org> List-Id: Gentoo Linux mail <gentoo-user.gentoo.org> X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 Sender: paul.hartman@gmail.com Received: by 10.150.229.15 with HTTP; Fri, 26 Mar 2010 15:50:06 -0700 (PDT) In-Reply-To: <201003262047.55200.expendable.0@danielquinn.org> References: <201003262047.55200.expendable.0@danielquinn.org> Date: Fri, 26 Mar 2010 17:50:06 -0500 X-Google-Sender-Auth: f9b61577c54484d9 Received: by 10.150.118.31 with SMTP id q31mr2073430ybc.58.1269643807179; Fri, 26 Mar 2010 15:50:07 -0700 (PDT) Message-ID: <58965d8a1003261550g6da01b74qf54574e8527a9781@mail.gmail.com> Subject: Re: [gentoo-user] CPU "choking" under high load From: Paul Hartman <paul.hartman+gentoo@gmail.com> To: gentoo-user@lists.gentoo.org Content-Type: text/plain; charset=ISO-8859-1 X-Archives-Salt: a64c3155-99b4-48d6-a9d7-c24221628133 X-Archives-Hash: 77567f583cfcdbf034bb920ca6209c5b On Fri, Mar 26, 2010 at 3:47 PM, Daniel Quinn <expendable.0@danielquinn.org> wrote: > I don't know if this is a hardware issue or not, but I thought that maybe I'd > configured my kernel incorrectly and that this might be a known issue someone > here has run across in the past so here goes: > > My computer is a pretty impressive AMD 64 X2 Dual Core Processor 6400+ box > with 2GB of RAM and for the most part, I just use it to write code at work. > However, whenever I'm doing something CPU-intensive, two things happen: > > * The load on the box goes up to 4 > * The box intermittently wobbles from running at full-speed and dropping to > a crawl. This is best seen while watching Flash videos online, > compressing/encoding video, or compiling. Everything is fine for a few > minutes, then suddenly the rate of compiling/compression/playback etc. > drops to a crawl for about 1-3minutes, then back up to full speed. > > I don't know why it's happening. I've tried various kernel options with no > change in behaviour. Outside of that though, I don't know what to try. > Suggestions welcome :-( My initial thoughts, it sounds like what I experienced a few kernels ago when they introduced the new group scheduler features. In my case I disabled "Group CPU scheduler" in kernel config and changed from SLUB back to SLAB. Also perhaps try to change your preemption model, timer frequency, NO_HZ mode. These things have all had noticeable differences to me in responsiveness over the years. If it's not a kernel issue, perhaps use "nice" to tame CPU-hungry processes, or "ionice" if they are disk-intensive. Be sure your Video Card is not overheating or going into low-power mode. Nvidia cards go into a super-slow-mode when they overheat (happened to me 3 times when the fan on the card died). When that happened, for example my FPS in glxgears would go from thousands down to double digits... I could see lines painting on the screen, it was painfully slow. Also, if your CPU has frequency scaling make sure it's not gone crazy, cat /proc/cpuinfo to see CPU speed, or powertop might be a more friendly way to view the P-States. Download memtest86+ from memtest.org and run it to be sure you don't have any faulty RAM (in my experience tests 5 and 8 are the only ones that ever show any errors, so you can save time by only running one full pass of all tests and then a multiple passes of 5 and 8 just to be sure it's good)