Messages in this thread | | | Subject | Re: Uptime counter | From | Matthew Reppert <> | Date | Sun, 01 Feb 2004 15:20:18 -0600 |
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On Sun, 2004-02-01 at 16:07, Ludootje wrote: > On Sun, 2004-02-01 at 20:51, Matti Aarnio wrote: > > On Sun, Feb 01, 2004 at 10:41:41PM +0200, Markus Hästbacka wrote: > > > Hi list, > > > I wonder does any kernel branch have a uptime counter that doesn't stop > > > counting at 497 days? Or is a patch needed for the job to > > > 2.{0,2,4,6} kernel? > > > > Any 64 bit machine since day 1, but also 2.6 at i386 does work. > > > > > Markus > > > > /Matti Aarnio > > It's the first time I hear about the uptime being resetted after 497 days, > why is this? Is this a mistake or are their reasons for it?
On 32-bit architectures, the uptime counter is only 32 bits wide. Each "tick" of the counter is worth 1/HZ seconds (IIRC). So, you can get the number of seconds this will hold with simple math (2^32 * 1/HZ, HZ being 100 on i386). This is about 497.1 days.
Of course, on 64-bit architectures, the counter will hold 4 billion times that, which is about as long as the Earth has existed. Apparently 2.6 has come up with a way to deal with this on 32-bit architectures.
Matt [unhandled content-type:application/pgp-signature] | |