Re: [PATCH *] use 64 bit jiffies

Matti Aarnio
2003-02-03T08:18:31Z

On Mon, Feb 03, 2003 at 08:42:59AM +0200, Denis Vlasenko wrote:
> On 3 February 2003 00:55, Tim Schmielau wrote:
> > Just a note that I have rediffed for 2.5.55 the patches that use the
> > 64 bit jiffies value to avoid uptime and process start time wrap
> > after 49.5 days. I will push them Linus-wards when he's back.
> > They can be retrieved from
....
> Wow... your patches are STILL not included??
> My 2.4 based server approaches 250 days uptime, it would be a shame
> to be unable to have uptime < 50 days with 2.5

You don't need to have 64-bit jiffy for things like internal
timers, nor for uptime tracking.

Timers have well behaving constructs to use 32-bit jiffy quite
successfully, and 64-bit values, especially atomicish, in 32-bit
register-poor machines (i386) are damn difficult.

I do have a number of machines with 100 to 300 day uptimes, all
with "mere" 32-bit jiffy. With 1000 Hz clock that means at least
one full wrap-around of jiffy.

> --
> vda

/Matti Aarnio