Re: strange timestamp in dmesg

From: Andi Kleen
Date: Fri Jun 06 2008 - 14:31:21 EST


On Fri, Jun 06, 2008 at 11:25:47AM -0700, Andrew Morton wrote:
> We've seen a storm of hey-my-timestamps-went-weird reports in just the
> past month or so. I don't recall it being (such) a problem before that.
>
> Did we change something

Nominally not, but who really knows with 5 digit number worth of changesets?

At least 64bit should have been always like this, but you only
see it on specific circumstances.

> > I always advocated just always using jiffies for printk. The only drawback would
> > be that it won't increase in interrupt off sections, but if you have
> > one that is longer than a jiffie then you have enough other problems.
>
> I forget why, but we _were_ going to have an (arch-overrideable)
> printk_clock() function. And we still could. The x86 implementation
> of that could fall back to jiffies if the TSCs are out of whack?

The rewritten sched_clock I used to plug, but which yielded about
zero interest, had one.

-Andi

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