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Full Discussion: semaphore access speed
Top Forums Programming semaphore access speed Post 302237947 by migurus on Thursday 18th of September 2008 05:58:19 PM
Old 09-18-2008
I replaced the ftime with gettimeofday and re-run, the results are the same.

To summarize again,
same h/w :
program under SCO runs 3 times faster than under Linux,
same OS :
program runs 2 times faster on old PIII than on modern Xeon

Any reasons? any ideas?
 

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ftime(2)							System Calls Manual							  ftime(2)

NAME
ftime - get date and time more precisely SYNOPSIS
Remarks This facility is provided for backwards compatibility with Version 7 systems. Either or should be used in new programs. DESCRIPTION
fills in a structure pointed to by its argument, as defined by /* * Structure returned by ftime system call */ struct timeb { time_t time; unsigned short millitm; short timezone; short dstflag; }; The structure contains the time in seconds since 00:00:00 UTC (Coordinated Universal Time), January 1, 1970, up to 1000 milliseconds of more-precise interval, the local timezone (measured in minutes of time westward from UTC), and a flag that, if nonzero, indicates that Day- light Saving time applies locally during the appropriate part of the year. Consult gettimeofday(2) for more details on the meaning of the timezone field. can fail for exactly the same reasons as gettimeofday(2). WARNINGS
The millisecond value usually has a granularity greater than one due to the resolution of the system clock. Depending on any granularity (particularly a granularity of one) renders code non-portable. SEE ALSO
date(1), gettimeofday(2), stime(2), time(2), ctime(3C). STANDARDS CONFORMANCE
ftime(2)
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