From owner-freebsd-virtualization@FreeBSD.ORG Sat Apr 11 04:27:20 2015 Return-Path: Delivered-To: freebsd-virtualization@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 2606B297 for ; Sat, 11 Apr 2015 04:27:20 +0000 (UTC) Received: from mail-wg0-x231.google.com (mail-wg0-x231.google.com [IPv6:2a00:1450:400c:c00::231]) (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 ADB3F945 for ; Sat, 11 Apr 2015 04:27:19 +0000 (UTC) Received: by wgso17 with SMTP id o17so34377359wgs.1 for ; Fri, 10 Apr 2015 21:27:18 -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=GROS7CLt59fWs26K+2D+CsmAyYjX6VJMHsIUACw7MvY=; b=tciIFOhdpP4zIWtLWeWZykCxbgM8GrDA8AgD2wIlKHepE+PIMCS61NOaGt99Ld238m CsP4W6WzCC3KC4KrQAKbUpg6Gxd2SCA3Zh6Ae8wPS397XjZ7JAyGQeyTYtGgZ98KvTp+ rbuHyxBr8e/b8rp5QBKbne6Lyhwo1RYBlEMGDBpL0gFqdLh3+ekDGxxmZ3CRsR4HH40e OD52F0PjSTCdF3DlIsZF5BrYpelh1FV8wKGIF8UNd6HPE3Qw0vsiE0/Sj/KXbzIk7GpS e1S/Mnuf0mUmKdo0AXhnBjaLHRo0jGkYjat6pfLMhstzkNG6p4P1whtbb+ODmXF08EJP Vdlw== MIME-Version: 1.0 X-Received: by 10.194.6.228 with SMTP id e4mr8387159wja.63.1428726438125; Fri, 10 Apr 2015 21:27:18 -0700 (PDT) Received: by 10.27.9.9 with HTTP; Fri, 10 Apr 2015 21:27:18 -0700 (PDT) In-Reply-To: <552852FB.1060901@shrew.net> References: <552809F4.6070206@redbarn.org> <552852FB.1060901@shrew.net> Date: Fri, 10 Apr 2015 21:27:18 -0700 Message-ID: Subject: Re: bhyve clock problem, solved by kern.timecounter.hardware="TSC-low" in /etc/sysctl.conf From: Neel Natu To: Matthew Grooms Content-Type: text/plain; charset=UTF-8 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: Sat, 11 Apr 2015 04:27:20 -0000 Hi, On Fri, Apr 10, 2015 at 3:47 PM, Matthew Grooms wrote: > Perhaps applying this commit would have some positive effect ( HPET vs LAPIC > )? > > https://docs.freebsd.org/cgi/getmsg.cgi?fetch=885358+0+archive/2015/svn-src-head/20150322.svn-src-head > No, it's an orthogonal change. The change above only causes the APIC to be preferred as an event timer (i.e. nothing to do with the choice of timecounter). best Neel > -Matthew > > > On 4/10/2015 12:51 PM, Stephen Stuart wrote: >> >> 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" >>> >> _______________________________________________ >> 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" > > > _______________________________________________ > 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"