From owner-freebsd-questions@FreeBSD.ORG Sat Feb 14 19:17:09 2015 Return-Path: Delivered-To: freebsd-questions@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 86436EF6 for ; Sat, 14 Feb 2015 19:17:09 +0000 (UTC) Received: from sasl.smtp.pobox.com (pb-sasl1.int.icgroup.com [208.72.237.25]) by mx1.freebsd.org (Postfix) with ESMTP id 4CDD6A17 for ; Sat, 14 Feb 2015 19:17:08 +0000 (UTC) Received: from sasl.smtp.pobox.com (unknown [127.0.0.1]) by pb-sasl1.pobox.com (Postfix) with ESMTP id 3E3F7356F6; Sat, 14 Feb 2015 14:17:07 -0500 (EST) DKIM-Signature: v=1; a=rsa-sha1; c=relaxed; d=pobox.com; h=subject :mime-version:content-type:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; s=sasl; bh= Y3Jq0HYj/mt1HRsgvu1vQN8rgLw=; b=ZtMUKVxFyPlV1puYWU8O9+N4psejC/wY fD2swuMZJxVFLkxP0TKUZls9JEK+cIwSmIwrKOzcOAbY0L5BosYJtwu8d1Rt5/6s 7+U13cLZfltGmpUJ2hnLzUT6ga6rCb7rjohOwSk+G5WLHtHkrZCCy5yCSnQ9QCUi wkqv+9UvDSs= DomainKey-Signature: a=rsa-sha1; c=nofws; d=pobox.com; h=subject :mime-version:content-type:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; q=dns; s= sasl; b=xMT8xIj7s/esKBGSdPIclzb6o1rcDi7ATJaNnYGtY6D+4zAWy92ct99r YhZ9WVMhykCFt6/3ecEn7iX8AQWfJ9blCFkhz2/tsjKO/4+HK6lm0epNzuPoKX7I wEkE6k5c0w5EZge04Cb2X3Qk8oky48RNzVKJFhrA6uiZvwxT96A= Received: from pb-sasl1.int.icgroup.com (unknown [127.0.0.1]) by pb-sasl1.pobox.com (Postfix) with ESMTP id 2981E356F5; Sat, 14 Feb 2015 14:17:07 -0500 (EST) Received: from almini.rcthomas.org (unknown [208.53.120.31]) (using TLSv1 with cipher ECDHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by pb-sasl1.pobox.com (Postfix) with ESMTPSA id 38C49356F4; Sat, 14 Feb 2015 14:17:06 -0500 (EST) Subject: Re: How to adjust clock frequency in FreeBSD 10.1 ? Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) Content-Type: text/plain; charset=windows-1252 From: Rick Thomas In-Reply-To: Date: Sat, 14 Feb 2015 11:17:03 -0800 Content-Transfer-Encoding: quoted-printable Message-Id: <2F352B9F-A1CA-47D3-B17D-4C7918B80636@pobox.com> References: To: Adam Vande More X-Mailer: Apple Mail (2.1878.6) X-Pobox-Relay-ID: 10C396A4-B47E-11E4-927E-8FDD009B7A5A-02150157!pb-sasl1.pobox.com Cc: FreeBSD Questions X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 14 Feb 2015 19:17:09 -0000 On Feb 14, 2015, at 4:50 AM, Adam Vande More = wrote: > On Sat, Feb 14, 2015 at 5:42 AM, Rick Thomas = wrote: >=20 >> When I try to change the frequency with (e.g.) >> sysctl kern.timecounter.tc.timebase.frequency=3D36000000 >>=20 >> I get >> sysctl: oid =91kern.timecounter.tc.timebase.frequency' is read = only >>=20 >=20 > Yeah, pretty clear that sysctl isn't going to help you in any way in = "man 4 > timecounters" >=20 > Is there some other way to set the frequency? >>=20 >=20 > Sure, but I thought keeping accurate time was the goal? If so, = sharing the > output from the first command I gave you is a good start. Ooops=85 Sorry! I thought I had already done that. In any case, here = it is: > [root@grey ~]# sysctl kern.timecounter > kern.timecounter.fast_gettime: 1 > kern.timecounter.tick: 1 > kern.timecounter.choice: timebase(0) dummy(-1000000) > kern.timecounter.hardware: timebase > kern.timecounter.alloweddeviation: 5 > kern.timecounter.stepwarnings: 0 > kern.timecounter.tc.timebase.mask: 4294967295 > kern.timecounter.tc.timebase.counter: 1981288884 > kern.timecounter.tc.timebase.frequency: 33290001 > kern.timecounter.tc.timebase.quality: 0 > [root@grey ~]#=20 I=92m guessing that by tuning the timebase.frequency number, I can make = the clock run effectively slower or faster. If I find the right value, = I can correct the problem I=92m seeing with ntpd. In case it matters, this is a powerpc Macintosh G4, so the only = available timecounter is =93timebase=94. Switching to a different = timecounter is not an available option. Rick=