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Subject:	Re: Final version of gettimeofday() patch
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From:	Gordon DOT Schumacher AT seagate DOT com
Date:	Thu, 1 Mar 2007 10:28:44 -0700
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Brian Inglis <Brian DOT Inglis AT SystematicSw DOT ab DOT ca> wrote on 02/28/2007 10:28:31
PM:

# Can someone please check if this is correct and feasible.
# The exact clock rate is 7*5*3*10^6/11/2^19 == 105*10^6/88/2^16 Hz.

I'll take your word for it, but I also trust the number that I've
already got in that file since I've tested it one several machines :)

# Could we do:
#
# typedef unsigned long long int clock_t
# #define CLOCKS_PER_SEC 1000000
# clock() == (rawclock() << 16)*88/105
#
# This would give us a pretty good integer approximation but with unsigned
# int we get a period of just less than 01:11:35 before clock() overflows.

I'm not trying to replace clock() at this point, just trying to
rewrite gettimeofday() so that it's not making a pair of int21
calls on every pass.  The gettimeofday() function gets used in
some performance-critical code (such as the Pth threading library)
so I'm trying to make it as fast as possible.

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