From owner-freebsd-hackers  Thu Aug 30  6:42:41 2001
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From: Bsdguru@aol.com
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Date: Thu, 30 Aug 2001 09:41:48 EDT
Subject: Re: Clock speedup on 4.X FreeBSD SMP and serverworks chipset
To: mb@imp.ch
Cc: hackers@freebsd.org
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In a message dated 8/30/01 7:44:23 AM Eastern Daylight Time, mb@imp.ch writes:

> Searching the freebsd mailinglists I have seen that you also suffering
>  under this problem on 4.X. STABLE:
>  
>  I have isolated the problem to be due reading the time with microtime()
>  
>  Execute this programm:
>  
>  #include <sys/types.h>
>  #include <sys/time.h>
>  #include <err.h>
>  
>  int
>  main(void)
>  {
>  
>         for(;;) {
>                 struct timeval tv;
>                 struct timezone tz;
>                 gettimeofday(&tv, &tz);
>         }
>         return (0);
>  }
>  
>  and you will see a 10% timedrift. For 20 seconds, I get 2 second
>  time speedup.
>  
>  You should not see this time drift if you remove the gettimeofday()
>  syscall of the programm.
>  
>  If someone has a machine where he can install CURRENT, or has a machine
>  with ServerWorks Chipset and SMP, is it possible that he can activate
>  ACPI and test it again ?
>  
>  There is already a PR, PR kern/30135.
>  

maybe the millions of system calls to the time function has something to do 
with the effect? 

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