Re: Why HZ on i386 is 100 ?

Andreas Dilger (adilger@clusterfs.com)
Tue, 16 Apr 2002 16:56:31 -0600

On Apr 17, 2002 08:37 +1000, Herbert Xu wrote:
> Why are we still measuring uptime using the tick variable? Ticks != time.
> Surely we should be recording the boot time somewhere (probably on a
> file system), and then comparing that with the current time?

Er, because the 'tick' is a valid count of the actual time that the
system has been running, while the "boot time" is totally meaningless.
What if the system has no RTC, or the RTC is wrong until later in the
boot sequence when it can be set by the user/ntpd? What if you pass
daylight savings time? Does your uptime increase/decrease by an hour?

Cheers, Andreas

--
Andreas Dilger
http://www-mddsp.enel.ucalgary.ca/People/adilger/
http://sourceforge.net/projects/ext2resize/


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