Date: Sun, 2 Jan 2000 16:45:19 -0600 From: Karl Denninger <karl@Denninger.Net> To: Warner Losh <imp@village.org> Cc: current@FreeBSD.ORG Subject: Re: xntpd - VERY old folks, how about updating? :-) Message-ID: <20000102164519.A25992@Denninger.Net> In-Reply-To: <200001022242.PAA31877@harmony.village.org>; from Warner Losh on Sun, Jan 02, 2000 at 03:42:24PM -0700 References: <20000102161029.A25883@Denninger.Net> <20000102103732.A23004@Denninger.Net> <20000102094459.B22738@Denninger.Net> <8426.946828544@critter.freebsd.dk> <20000102103732.A23004@Denninger.Net> <200001022133.OAA31402@harmony.village.org> <20000102161029.A25883@Denninger.Net> <200001022232.PAA31807@harmony.village.org> <20000102163802.A25936@Denninger.Net> <200001022242.PAA31877@harmony.village.org>
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On Sun, Jan 02, 2000 at 03:42:24PM -0700, Warner Losh wrote: > In message <20000102163802.A25936@Denninger.Net> Karl Denninger writes: > : And on what hardware do you think you can obtain 10ns resolution RELIABLY > : at the software level in the Unix environment and under FreeBSD? > : > : Answer: NONE! > > WRONG. > > : The actual usable resolution of a timing source is determined by the > : maximum slop in ANY part of the complete system. > : > : I challenge you to get actual REPEATABLE 10ns results while a multi-tasking > : anything is running on the recipient of that data. > > We have hardware timers that let us get into the pico second range on > a regular basis. > > Warner Yes, you have HARDWARE timers that do that. So what? I'm talking about TIME SERVERS on UNIX machines. You know, ntpd and friends? Yes, that. Now explain to me how stability of your timing source ON THOSE MACHINES is MATERIALLY different to any process WHICH THAT DEVICE MAY INTERACT WITH between 10ns and 1us, AS SEEN FROM THE UNIX MACHINE. I'm simply not interested in NON-GERMANE devices to the discussion; we were talking about FreeBSD on REAL computers, not specialty hardware for process control or nuclear physics experiments. -- -- Karl Denninger (karl@denninger.net) Web: http://childrens-justice.org Isn't it time we started putting KIDS first? See the above URL for a plan to do exactly that! To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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