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Date:      Fri, 26 Oct 2001 14:13:11 -0700 (PDT)
From:      Matthew Dillon <dillon@apollo.backplane.com>
To:        John Baldwin <jhb@FreeBSD.ORG>, Poul-Henning Kamp <phk@critter.freebsd.dk>, arch@FreeBSD.ORG, Peter Wemm <peter@wemm.org>, Bakul Shah <bakul@bitblocks.com>
Subject:   Re: 64 bit times revisited..
Message-ID:  <200110262113.f9QLDBJ38657@apollo.backplane.com>
References:  <XFMail.011026131501.jhb@FreeBSD.org> <200110262108.f9QL8n238592@apollo.backplane.com>

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:
:
::> 
::> If you look in sys/kern/kern_tc.c you can see how much extra
::> gunk that results in, checking for overruns on the middle part and
::> whats not.
::> 
::> There can be no doubt that the best timestamp representation is
::> pure binary, originating at the second, and that is how my proposal
::> is constructed:
::> 
::> <-- 32bit --><-- 32bit --> . <-- 32bit --><-- 32bit -->
::>       1            2               3            4
::
::IOW, a fixed-point number.  This is definitely the optimal solution presented
::so far for the in-kernel time keeping, IMO.

   And I will also note that trying to represent both seconds and sub-seconds
   in a single fixed point integer is a real bad idea.  It makes life
   unnecessarily difficult for the 95% of the code that only needs the
   seconds portion.  Any fractional representation should be a SEPARATE 
   field.

   We will have time_t, in seconds, and we can have struct ntm representing
   both the seconds and fractional portions (as separate fields).

						-Matt


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