Messages in this thread | | | Date | Wed, 20 Feb 2002 08:50:32 -0800 | From | george anzinger <> | Subject | Re: jiffies rollover, uptime etc. |
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Bill Davidsen wrote: > > On Tue, 19 Feb 2002, george anzinger wrote: > > > Bill Davidsen wrote: > > > > > > On Mon, 18 Feb 2002, Ben Greear wrote: > > > > > Does this problem still exist on 64-bit machines? > > > > > > Absolutely. But not as often ;-) > > > > Actually you will have a VERY hard time getting it to roll over. Issues > > of your life time, not to mention the hardware's life time. 64 bits > > makes a VERY large number and you are counting in 427 day increments. > > Remember we have been counting seconds since 1970 in 32 bits and > > rollover is still, most likely, beyond the capability of any machine > > running today to get to. Now consider counting in 427 day increments > > instead of seconds. > > Um, note the odd characters appended to my sentence ";-)" which means > "not serious here, look for joke, sarcasm, over or understatement. > Ok, I guess I just got so impressed with the size of a 64-bit value that I was overwhelmed. Consider, for example:
u64 i; for (i = 1; i != 0; i++);
Now in theory this will count each possible number, but in practice the machine will die long before it ever finishes.
-- George george@mvista.com High-res-timers: http://sourceforge.net/projects/high-res-timers/ Real time sched: http://sourceforge.net/projects/rtsched/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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