Date: Thu, 16 Jul 1998 09:23:27 +0200 From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: jak@cetlink.net (John Kelly) Cc: Bruce Evans <bde@zeta.org.au>, current@FreeBSD.ORG Subject: Re: tickadj -t not changing tick Message-ID: <278.900573807@critter.freebsd.dk> In-Reply-To: Your message of "Thu, 16 Jul 1998 06:19:36 GMT." <35ad9407.200559635@mail.cetlink.net>
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In message <35ad9407.200559635@mail.cetlink.net>, John Kelly writes: >On Wed, 15 Jul 1998 13:30:29 +1000, Bruce Evans <bde@zeta.org.au> >wrote: > >>machdep.i8254_freq: always exists, never hurts to set it right, but only >> essential for it to be right on systems using it for timekeeping >> (2.2., -current on sub-586's and 586+'s running SMP or APM. > >Sysctl shows my default value of machdep.i8254_freq = 1,193,182, the >same value one of my hardware books says is the "standard" oscillator >rate input to the 8254. But since my clock runs fast, my oscillator >seems to be at a slightly higher rate. So am I correct in assuming I >need to increase the i8254_freq value to match the true oscillator >rate, and the kernel will adjust accordingly? > >And besides trial and error, is there any way of determining what the >true frequency of my oscillator is? You want to fiddle kern.timecounter.frequency (units: Hz) or kern.timecounter.adjustment (Units: PPM/2^16) The real way is to run ntpd, if you don't have a permanent connection, consider looking into "burstmode" in the new xntpd4... >I know what the 8254 is, but what is the TSC? A 64 bit counter internal to the Pentium, which counts clockcycles... -- Poul-Henning Kamp FreeBSD coreteam member phk@FreeBSD.ORG "Real hackers run -current on their laptop." "ttyv0" -- What UNIX calls a $20K state-of-the-art, 3D, hi-res color terminal To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message
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