Date: Thu, 30 Aug 2001 09:41:48 EDT From: Bsdguru@aol.com To: mb@imp.ch Cc: hackers@freebsd.org Subject: Re: Clock speedup on 4.X FreeBSD SMP and serverworks chipset Message-ID: <14b.2a17a2.28bf9c9c@aol.com>
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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? To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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