Date: Mon, 30 Nov 1998 20:19:15 +0100 From: Poul-Henning Kamp <phk@critter.freebsd.dk> To: John Hay <jhay@mikom.csir.co.za> Cc: cvs-committers@FreeBSD.ORG, cvs-all@FreeBSD.ORG Subject: Re: cvs commit: src/sys/kern kern_clock.c Message-ID: <12990.912453555@critter.freebsd.dk> In-Reply-To: Your message of "Sat, 30 Nov 1998 21:02:21 %2B0200." <199811301902.VAA15840@zibbi.mikom.csir.co.za>
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In message <199811301902.VAA15840@zibbi.mikom.csir.co.za>, John Hay writes: >> >> > We would *not* use the 82C54's timer registers to >> > actually try to read out the counter at all unless we were running on >> > much older cpu's. >> >> We do just that, unless it is a SMP, in which case we would need to >> synchronize the TSC of the cpus before we can use them. (If only Intel >> hadn't yanked the timer from the IO-APIC!) > >Dave Mills have written code to sync the TSCs on the alphas in Digital >Unix. In principal he (and a guy from Digital) have already agread to >make it available to us, but first he have to get it out of the digital >code without any proprietry pieces comming along. I'm currently discussing this with Dave Mills, because I think that code is overkill. He is using a (software-PLL) to keep them in step, but in reality, I don't think they can diverge if you get them synchronized once. Certainly the i386 cpus generate their cpuclock with a PLL locked to the bus clock, I belive the alpha does the same thing, right ? -- 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 cvs-all" in the body of the message
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