From owner-freebsd-stable@FreeBSD.ORG Tue Oct 11 21:14:09 2011 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 41892106566B; Tue, 11 Oct 2011 21:14:09 +0000 (UTC) (envelope-from artemb@gmail.com) Received: from mail-gy0-f182.google.com (mail-gy0-f182.google.com [209.85.160.182]) by mx1.freebsd.org (Postfix) with ESMTP id D42C28FC13; Tue, 11 Oct 2011 21:14:08 +0000 (UTC) Received: by gyf2 with SMTP id 2so23168gyf.13 for ; Tue, 11 Oct 2011 14:14:08 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=mime-version:sender:in-reply-to:references:date :x-google-sender-auth:message-id:subject:from:to:cc:content-type; bh=236ixAz5gHb3LrxRmlAUWXKii6lYGw/7f9DEjEJEYQI=; b=Zrp5RmuFWMmpS8DoELuAkV/5m//xbVyEjkjyZsiPDyTCtdppYwOoUgjdtVJ9MeEEEk IFCN4szFfotMM8Fi75YOV2UqZdyeaRbyrsF0JlAMdjyv6WeiHKxLiN+cLVOHIxnLioO+ Qea5PqCLPzYtmV1EuvAbLWouPgX89sJvFFNiA= MIME-Version: 1.0 Received: by 10.236.187.101 with SMTP id x65mr29281849yhm.63.1318367647929; Tue, 11 Oct 2011 14:14:07 -0700 (PDT) Sender: artemb@gmail.com Received: by 10.236.103.33 with HTTP; Tue, 11 Oct 2011 14:14:07 -0700 (PDT) In-Reply-To: References: <20101116003029.GC79816@numachi.com> <20101116125431.GA90475@icarus.home.lan> <852472071289497FA806928D0B41D0FE@multiplay.co.uk> Date: Tue, 11 Oct 2011 14:14:07 -0700 X-Google-Sender-Auth: SzJSgoepQfONqp0j4jQrGUSgDqA Message-ID: From: Artem Belevich To: Steven Hartland Content-Type: text/plain; charset=ISO-8859-1 Cc: =?ISO-8859-1?Q?Micka=EBl_Maillot?= , Christer Solskogen , freebsd-stable@freebsd.org, Ivan Voras , Jeremy Chadwick Subject: Re: "High" cpu usage when using ZFS cache device 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: Tue, 11 Oct 2011 21:14:09 -0000 On Tue, Oct 11, 2011 at 1:17 PM, Steven Hartland wrote: >> It's a bummer. If you can build your own kernel cherry-picking >> following revisions may help with long-term stability: >> r218429 - fixes original overflow causing CPU hogging by l2arc feeding >> thread. It will keep you up and running for longer until you hit >> another overflow. If I remember correctly, it will hit you around >> 100-days of uptime. > > This is the main issue we have been keeping an eye out for as we've > seen it several times, we don't have too many machines with L2ARC so > was surprised to see this with just 26 days up time in this case. > >> Following changes were done after ZFSv28 import, so they will not >> apply directly to 8-RELEASE, but the idea applies to ZFSv15 as well. >> The changes should be easy to backport. >> >> r223412 - avoids more early overflows in time routines. >> r224647 - avoids time overflow in TXG processing. > > We already maintain a custom set of patches for our 8.2 installs so > shouldn't be an issue to add these so thanks for the info :) > > With all three should we expect no uptime overflow issues or still are > we still going to look at ~100 day reboots required? Those should get you through the known (to me) sources of LBOLT and clock_t related overflows. Can't say whether you'll run into some other problems. --Artem