From owner-freebsd-current@freebsd.org Tue Oct 24 21:44:10 2017 Return-Path: Delivered-To: freebsd-current@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id A3AA7E2F8C5; Tue, 24 Oct 2017 21:44:10 +0000 (UTC) (envelope-from bsam@passap.ru) Received: from forward100o.mail.yandex.net (forward100o.mail.yandex.net [IPv6:2a02:6b8:0:1a2d::600]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "forwards.mail.yandex.net", Issuer "Yandex CA" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 4298872409; Tue, 24 Oct 2017 21:44:09 +0000 (UTC) (envelope-from bsam@passap.ru) Received: from mxback13g.mail.yandex.net (mxback13g.mail.yandex.net [IPv6:2a02:6b8:0:1472:2741:0:8b7:92]) by forward100o.mail.yandex.net (Yandex) with ESMTP id 5A26E2A20377; Wed, 25 Oct 2017 00:43:57 +0300 (MSK) Received: from smtp3p.mail.yandex.net (smtp3p.mail.yandex.net [2a02:6b8:0:1472:2741:0:8b6:8]) by mxback13g.mail.yandex.net (nwsmtp/Yandex) with ESMTP id isWUQvay8k-hvvS5KMY; Wed, 25 Oct 2017 00:43:57 +0300 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=passap.ru; s=mail; t=1508881437; bh=RybvAS57SQL0OlWyT48G8jgsB5KnBTAJw8AokO4jpDE=; h=Subject:To:Cc:References:From:Message-ID:Date:In-Reply-To; b=fISIJ3lLtL4Wfd8bMcikB/sNYmdoMov0bewoct/quOsWD5tdydtof/JZh99isl4jc 6sW8O5dM2fjY+0XvM0aTM/2/tMOLWL7gRbGf8i/2Ikvg8aEKJYvXgLXUskfY9Xm0Up lr2VsEA0JOKZ4jy+gIYV0didQtLxmDpUiacyJdrY= Received: by smtp3p.mail.yandex.net (nwsmtp/Yandex) with ESMTPSA id 4fevxQ2hI4-hugGLx6g; Wed, 25 Oct 2017 00:43:56 +0300 (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client certificate not present) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=passap.ru; s=mail; t=1508881436; bh=RybvAS57SQL0OlWyT48G8jgsB5KnBTAJw8AokO4jpDE=; h=Subject:To:Cc:References:From:Message-ID:Date:In-Reply-To; b=eoCyv7nbmCCPvMMlygvjslnGgL4kWxeV3RsN4Ncjci/EY9eWr5adiXjJAsDnlRSzi 1A43f6wBQ04Vhy9ae1SQbjJ9i/bNCKr8KhWjELaT+bZFRyq8HQygFhsLp7i6Qp/qdX oNpeN3As7Wj0aB6wNGDdhc/8uZ4hL2mSvrito8+Q= Authentication-Results: smtp3p.mail.yandex.net; dkim=pass header.i=@passap.ru Subject: Re: host, bhyve vm and ntpd To: Ian Lepore , Michael Voorhis Cc: freebsd-current@FreeBSD.org, freebsd-virtualization@FreeBSD.org References: <2931f1cc-6574-b58d-4b94-5f77fa5cdb85@passap.ru> <1508512327.1383.55.camel@freebsd.org> <39bf2426-2edf-d485-7c81-519e931154be@passap.ru> <1508517160.1383.63.camel@freebsd.org> <76ff7afb-3d3a-96f6-1275-89472ff5683d@passap.ru> <1508522667.1383.69.camel@freebsd.org> <30992c14-7b78-ab9f-5693-931e6ca41f1b@passap.ru> <1508523696.1383.75.camel@freebsd.org> <23019.46875.929719.481108@atom.mcvau.net> <1508624153.1383.107.camel@freebsd.org> From: Boris Samorodov Message-ID: Date: Wed, 25 Oct 2017 00:43:56 +0300 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:52.0) Gecko/20100101 Thunderbird/52.4.0 MIME-Version: 1.0 In-Reply-To: <1508624153.1383.107.camel@freebsd.org> Content-Type: text/plain; charset=UTF-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 24 Oct 2017 21:44:10 -0000 Hi Ian, All! 22.10.2017 01:15, Ian Lepore пишет: > On Sat, 2017-10-21 at 17:07 -0400, Michael Voorhis wrote: >> Ian Lepore writes: >>> >>> Beyond that, I'm not sure what else to try.  It might be necessary to >>> get some bhyve developers involved (I know almost nothing about it). >> NTPD behaves more normally on uniprocessor VMs. >> >> A FreeBSD bhyve-guest running on a freebsd host will select a >> different timecounter depending on whether it is a multiprocessor or a >> uniprocessor.  My uniprocessor bhyve-vm selected TSC-low as the best >> timecounter in a uniprocessor.  NTP functions there as expected. >> >> kern.timecounter.choice: TSC-low(1000) ACPI-fast(900) HPET(950) i8254(0) dummy(-1000000) >> kern.timecounter.hardware: TSC-low >> >> The very same VM, when given two total CPUs, selected HPET (if I >> recall) and the timekeeping with NTPD was unreliable, with many >> step-resets to the clock. >> > > Hmm, I just had glance at the code in sys/amd64/vmm/io/vhpet.c and it > looks right.  I wonder if this is just a simple roundoff error in > converting between 10.0MHz and SBT units?  If so, that could be wished > away easily by using a power-of-2 frequency for the virtual HPET.  I > wonder if the attached patch is all that's needed? I suppose the answer is "yes", the patch helped. Here are two samples (host for bhyve VM without your patch and after patching): --- https://poudriere.passap.ru/misc/ntpd.jot.log-HPET.frequency.10000000.txt https://poudriere.passap.ru/misc/ntpd.jot.log-HPET.frequency.16777216.txt --- The command was: % for t in `jot 1000`; do ntpq -pn; sleep 64; done The patch made the system to stabilize the process. Ian, thank you! -- WBR, bsam