Article View: comp.protocols.time.ntp
Article #1014Re: Problems with xntp and MIPS RISC/os 5.01
From: Mills
Date: Wed, 13 Jan 1993 04:56
Date: Wed, 13 Jan 1993 04:56
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1355 bytes
Alan, First, make sure your clock has a resolution at least in the 10-20 ms range; if not, forget it. Then, start xntpd and watch the offsets right after startup. If there is a large frequency offset in your CPU, you will see a definite trend in offsets for the first few. If the difference in (smoothed) offsets from one sample to the next is more than one millisecond, your frequency is out of tolerance. Run your CPU for a day without outside synchronization and, using a wristwatch and deft fingers, try to estimate the frequency error in parts per million. Then, tickle adjtime to compensate for it, about one part in 10,000 for each 100 ppm. You get to guess the sign - I forget. Repeat the process until the frequency error is less than 100 ppm. This is all the help I can give. If your frequency error is less than 100 ppm and the stock code still jumps around, you need an operating- system guru, not a simple clockwatcher. Dave
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Path: arc1-ca.pugleaf.net!sparky!uunet!paladin.american.edu!howland.reston.ans.net!spool.mu.edu!agate!ucbvax!UDEL.EDU!Mills From: Mills@UDEL.EDU Newsgroups: comp.protocols.time.ntp Subject: Re: Problems with xntp and MIPS RISC/os 5.01 Message-ID: <9301122356.aa29908@huey.udel.edu> Date: 13 Jan 93 04:56:00 GMT Sender: daemon@ucbvax.BERKELEY.EDU Distribution: inet Organization: The Internet Lines: 19