64bit ticks, was Re: Changing p_swtime and td_slptime to ticks

Jeff Roberson jroberson at chesapeake.net
Tue Sep 18 19:15:17 PDT 2007

On Tue, 18 Sep 2007, Garrett Wollman wrote:

> Jeff Roberson writes:
>> Is there a good reason for not making ticks 64bit?  math involving this
>> value is relatively infrequent.  Bruce?  Any comments?  It'd sure let us
>> forget all of these counter wrapping problems.
> Making ticks 64 bits on 32-bit architectures means that updates to it
> will not be atomic.

You're right.  There would be a chance that you'd get mismatched upper and 
lower halves on wrap conditions and would have to detect accordingly. 
That's probably too much trouble.


> -GAWollman
> -- 
> Garrett A. Wollman   | The real tragedy of human existence is not that we are
> wollman at csail.mit.edu| nasty by nature, but that a cruel structural asymmetry
> Opinions not those   | grants to rare events of meanness such power to shape
> of MIT or CSAIL.     | our history. - S.J. Gould, Ten Thousand Acts of Kindness

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