Messages in this thread | | | Date | Wed, 28 Jul 1999 12:08:17 +0100 (GMT) | From | Riley Williams <> | Subject | Re: [PATCH] HZ==100 assumptions |
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Hi Pauline.
>>> Those drivers have been tested with HZ==100, but probably not >>> with any other value. Also if HZ is made very large (e.g. >>> microsecond accuracy) "defer as short as possible" is the wrong >>> behaviour.
>>> So IMHO those 1s should all be changed to HZ/100.
>> 1 jiffie != 1 s
> HZ/100 = 10ms which is a reasonable appr. for a 18.2ms jiffy > (ix86)
If a jiffie is indeed 18.2ms then HZ/100 is a good approximation to HALF a jiffie and HZ/50 a good approximation to one jiffie.
However, the standard used by MSDOS (which I assume is what you're referring to) is for the clock to tick ~18.2 times per second (to be more accurate, 65536 ticks per hour), in which case the correct definition would be that a jiffie is 5*HZ/91 and it can be approximated by HZ/18 - which is a long way from HZ/100 !!!
Q> # echo '12k 65536 3600 /p' | dc Q> 18.204444444444 Q> #
The above says "To 12 decimal places, show me the result of dividing 65536 by the 3600 seconds that make up an hour"...
Best wishes from Riley.
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