Date: Thu, 24 Mar 2011 17:19:28 -0600 From: Warner Losh <imp@bsdimp.com> To: John Baldwin <jhb@FreeBSD.org> Cc: svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org, src-committers@FreeBSD.org, Peter Jeremy <peterjeremy@acm.org>, Jung-uk Kim <jkim@FreeBSD.org> Subject: Re: svn commit: r219700 - head/sys/x86/x86 Message-ID: <4D8BD180.1060600@bsdimp.com> In-Reply-To: <201103230834.19151.jhb@freebsd.org> References: <201103161644.p2GGi8ug098283@svn.freebsd.org> <20110317200156.GB65858@server.vk2pj.dyndns.org> <201103171706.12993.jkim@FreeBSD.org> <201103230834.19151.jhb@freebsd.org>
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On 03/23/2011 06:34, John Baldwin wrote: > On Thursday, March 17, 2011 5:06:09 pm Jung-uk Kim wrote: >> On Thursday 17 March 2011 04:01 pm, Peter Jeremy wrote: >>> On 2011-Mar-16 16:44:08 +0000, Jung-uk Kim<jkim@FreeBSD.org> wrote: >>>> Log: >>>> Revert r219676. >>> Thanks also. For extra kudos, how about adding a similar function >>> to allow the HPET frequency to be over-ridden. That is currently >>> the only timecounter that does not allow the user to compensate for >>> incorrect hardware frequencies. >> I really hate the idea of adjusting timecounter frequency from >> userland. I guess "use ntpd(8)" is not a good answer for some >> people. :-( > Actually, that doesn't work well if your timecounter frequency is off by a > lot. Having the timecounter frequency accurate improves the accuracy of > things like ntpd and ptpd. ntpd requires that the time counter be within 128ppm of true. If the time counter guess is off by more than that, you lose: ntpd won't work. Warner
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