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DateTue, 15 Apr 2003 02:25:12 -0700
Fromgeorge anzinger <>
SubjectRe: [PATCH] Fix jiffies_to_time[spec | val] and converse to use actual jiffies increment rather than 1/HZ
Russell King wrote:
> On Tue, Apr 15, 2003 at 01:36:46AM -0700, george anzinger wrote:
> 
>>In the current system (2.5.67) time_spec to jiffies, time_val to 
>>jiffies and the converse (jiffies to time_val and jiffies to 
>>time_spec) all use 1/HZ as the measure of a jiffie.  Because of the 
>>inability of the PIT to actually generate an accurate 1/HZ interrupt, 
>>the wall clock is updated with a more accurate value (999848 
>>nanoseconds per jiffie for HZ = 1000).
> 
> 
> There's an increasing amount of 64-bit math appearing here, which gcc
> has been historically bad with.  Is there any chance that all this
> extra complexity can vanish for architectures which do not have this
> problem?

I suppose that is possible.  On the other hand, the only 64-bit things 
we leave to C are the "+" and shift.
> 

-- 
George Anzinger   george@mvista.com
High-res-timers:  http://sourceforge.net/projects/high-res-timers/
Preemption patch: http://www.kernel.org/pub/linux/kernel/people/rml

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