Re: [PATCH] Re: boot time, process start time, and NOW time

[john stultz]

On Tue, 2004-08-31 at 12:27, George Anzinger wrote:
> Tim Schmielau wrote:
> > On Mon, 30 Aug 2004, john stultz wrote:
> >>On Mon, 2004-08-30 at 16:00, Tim Schmielau wrote:
> >>
> >>>George, please excuse my lack of understanding. What again where the
> >>>precise reasons to have an ntp-corrected uptime?
> >>
> >>Ah, here's the thread with the first mention of it that I could find.
> >>
> >>http://www.uwsg.iu.edu/hypermail/linux/kernel/0306.1/1471.html
> 
> As I recall the problem was that jiffies since boot was being converted to get 
> uptime base on 1/HZ = 1 jiffie.  Since it is really not quite that, there was an 
> error.  Using clock_monotonic seemed like the right answer as it eliminated the 
> error AND made the result consistant with get_clock(CLOCK_MONOTONIC,..).
> 
> The alternate answer is, of course, to directly convert the elapsed jiffies. 
> The main problem with this is that this can be a BIG number and, therefor, the 
> math needs to be carefully.  And, of course, it is inconsistant with 
> get_clock(), but that is a new interface...

Hmmm. Well, I may be starting to lean in Tim's direction of pulling the
clock_monotonic based uptime and going back to the jiffies based uptime.
Atleast until we can make all the /proc/ output consistent. 

I just worry that it actually fixed a problem for someone, and backing
it out would just reopen that.

Thoughts?

-john


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/