Date: Fri, 25 Mar 2011 21:02:03 +1100 (EST) From: Bruce Evans <brde@optusnet.com.au> To: Warner Losh <imp@bsdimp.com> Cc: src-committers@freebsd.org, John Baldwin <jhb@freebsd.org>, Peter Jeremy <peterjeremy@acm.org>, svn-src-all@freebsd.org, svn-src-head@freebsd.org, Jung-uk Kim <jkim@freebsd.org> Subject: Re: svn commit: r219700 - head/sys/x86/x86 Message-ID: <20110325203713.K956@besplex.bde.org> In-Reply-To: <4D8BD180.1060600@bsdimp.com> References: <201103161644.p2GGi8ug098283@svn.freebsd.org> <20110317200156.GB65858@server.vk2pj.dyndns.org> <201103171706.12993.jkim@FreeBSD.org> <201103230834.19151.jhb@freebsd.org> <4D8BD180.1060600@bsdimp.com>
next in thread | previous in thread | raw e-mail | index | archive | help
On Thu, 24 Mar 2011, Warner Losh wrote: > On 03/23/2011 06:34, John Baldwin wrote: >> On Thursday, March 17, 2011 5:06:09 pm Jung-uk Kim wrote: >>> 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. Is ntpd really that broken? What does it do if the drift file has the correct compensation to within 128 ppm? I use an old version of ntpd in which I've observed a positive feedback loop when -x is used to prevent steps and the slew wants to be more than 128 ppm due to a transient. Bruce
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?20110325203713.K956>