Date: Wed, 1 Nov 1995 17:33:13 +0200 (SAT) From: John Hay <jhay@mikom.csir.co.za> To: bde@zeta.org.au (Bruce Evans) Cc: wollman@lcs.mit.edu, current@FreeBSD.org Subject: Re: Time problems Message-ID: <199511011533.RAA19641@zibbi.mikom.csir.co.za> In-Reply-To: <199511010903.UAA24620@godzilla.zeta.org.au> from "Bruce Evans" at Nov 1, 95 08:03:05 pm
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> > >OK, I changed the values in calibrate_cyclecounter() like suggested and now > >my time stay much closer to reality. > > >My CPU even probe as a 90MHz processor! > >> CPU: 90-MHz Pentium 735\\90 (Pentium-class CPU) > >> Origin = "GenuineIntel" Id = 0x525 Stepping=5 > >> Features=0x3bf<FPU,VME,PSE,MCE,CX8,APIC> > > >Can we get some kernel config option to do this or will I have to change > >clock.c after every ctm? Or will this get to be the default? > > No. Reducing the calibration time should just decrease the accuracy of > the calibration (and speed up the boot :-). Find out which clock is > inaccurate or which part of the calibration routine is buggy. Define > DELAYDEBUG to get some debugging code in clock.c. It currently > generates delays of powers of 10 usec up to 10 seconds. You could > increase the delats to 100, 1000, ... seconds and time them with a > stopwatch to see how accurate DELAY() is. > > Bruce > OK, I did that and the 10 second delay takes about 8.5 seconds and the 100 second delay takes about 88 seconds. Here is the first part of dmesg: CPU: DELAY(1)... 1 calls to getit() at -14 usec each DELAY(10)... 1 calls to getit() at -5 usec each DELAY(100)... 22 calls to getit() at 3 usec each DELAY(1000)... 261 calls to getit() at 3 usec each DELAY(10000)... 2648 calls to getit() at 3 usec each DELAY(100000)... 26511 calls to getit() at 3 usec each DELAY(1000000)... 238632 calls to getit() at 4 usec each DELAY(10000000)... 2351886 calls to getit() at 4 usec each DELAY(100000000)... 23667381 calls to getit() at 4 usec each 892492-MHz Pentium 735\\90 or 815\\100 (Pentium-class CPU) >From about 100000 the values that is being printed vary quite a lot between boots. Now how do I go further to find out where my problem is? John -- John Hay -- John.Hay@csir.co.za
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