From owner-freebsd-virtualization@FreeBSD.ORG Fri Apr 10 17:51:34 2015 Return-Path: Delivered-To: freebsd-virtualization@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 85297CE for ; Fri, 10 Apr 2015 17:51:34 +0000 (UTC) Received: from mail-qg0-x22e.google.com (mail-qg0-x22e.google.com [IPv6:2607:f8b0:400d:c04::22e]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 3B1F5C26 for ; Fri, 10 Apr 2015 17:51:34 +0000 (UTC) Received: by qgeb100 with SMTP id b100so1467618qge.3 for ; Fri, 10 Apr 2015 10:51:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=yQaefOSydaHc8rKPrBiHwyBtx1oPcalUvLKvSavNO9I=; b=DjbFmQVHB2IdxOT9Gj8xBo7ECLtJxqK9krIB4APfYd7Ki1HGDxXAdUh284dv14pHZO NhQvdNMJsE/zP6HreUcLD94BMx9EQsVJYIn6mXS4wsmwK4p5/Ruv77wW0c4y6ZyDY4d9 q2aGBZiXVnCI/+0P6q9qiiQB333hH9XFuf/pLnqU+/4FkodZlVrU2rbCTysGpuUzRqlY y7q2J0vDKUcQ0n72lkRXz+nz2loNErfpiLda7kedXfeTOS+2G4Oa//RtkJLlAx/nBAM+ vAKvJexUjU3mZNijQrW064+AECAy1Tz7PT1FtyglDsXWtiOnXufeTSkQkM9NozIoPcvw +fIg== MIME-Version: 1.0 X-Received: by 10.140.235.77 with SMTP id g74mr3461458qhc.64.1428688293510; Fri, 10 Apr 2015 10:51:33 -0700 (PDT) Received: by 10.140.104.44 with HTTP; Fri, 10 Apr 2015 10:51:33 -0700 (PDT) In-Reply-To: <552809F4.6070206@redbarn.org> References: <552809F4.6070206@redbarn.org> Date: Fri, 10 Apr 2015 10:51:33 -0700 Message-ID: Subject: Re: bhyve clock problem, solved by kern.timecounter.hardware="TSC-low" in /etc/sysctl.conf From: Stephen Stuart To: Paul Vixie Content-Type: text/plain; charset=UTF-8 X-Content-Filtered-By: Mailman/MimeDel 2.1.18-1 Cc: freebsd-virtualization@freebsd.org X-BeenThere: freebsd-virtualization@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: "Discussion of various virtualization techniques FreeBSD supports." List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 10 Apr 2015 17:51:34 -0000 I think the right thing is to set (in /boot/loader.conf) kern.timecounter.tc.TSC-low.quality to a value higher than that for HPET, to force the clock choice over what the kernel decides for the hardware that you're running on. See timecounters(4). Stephen On Fri, Apr 10, 2015 at 10:35 AM, Paul Vixie wrote: > here is a representative one-hour sample of ntp messages from > /var/log/messages on a freebsd 10.1 bhyve guest: > > > Apr 10 12:00:46 family ntpd[634]: time reset -0.613057 s > > Apr 10 12:17:02 family ntpd[634]: time reset -0.604933 s > > Apr 10 12:33:51 family ntpd[634]: time reset -0.650622 s > > Apr 10 12:55:06 family ntpd[634]: time reset -0.743930 s > > > that's with kern.timecounter.hardware: HPET, which is the default. > > a "time reset" from ntpd means the clock either won't slew at all or > can't slew fast enough. in other words a normal freebsd 10.1 server can > run for months or even years without ever outputting one of these messages. > > google reports that some folks have had good luck with > kern.timecounter.hardware: TSC-low. so i tried that on another freebsd > 10.1 bhyve guest on the same bhyve server, with dramatic results -- no > more ntpd messages. > > can we make TSC-low the default? > > vixie > > > _______________________________________________ > freebsd-virtualization@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-virtualization > To unsubscribe, send any mail to " > freebsd-virtualization-unsubscribe@freebsd.org" >