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Re: [Xen-devel] Kernel printk timestamps and walltime drift
| To: | Roger Cruz <rcruz@xxxxxxxxxxxxxxxxxxxxxxxx>, xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx> |
|---|---|
| Subject: | Re: [Xen-devel] Kernel printk timestamps and walltime drift |
| From: | Keir Fraser <keir.fraser@xxxxxxxxxxxxx> |
| Date: | Fri, 13 Jun 2008 21:31:18 +0100 |
| Delivery-date: | Fri, 13 Jun 2008 13:30:52 -0700 |
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| Thread-topic: | [Xen-devel] Kernel printk timestamps and walltime drift |
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On 13/6/08 21:10, "Roger Cruz" <rcruz@xxxxxxxxxxxxxxxxxxxxxxxx> wrote: > The walltime appears to be generated from periodic timer ticks that > update "xtime". These values have always been correct. Only the ones > that get generated with the vprintk appear to slip when compared to this > wall time. Yes, sched_clock() can drift relative to wall time. It's an internal monotonic timesource for the kernel, and if it drifts it doesn't usually matter. It's not visible to user space. So, that explains your vprintk timestamp drift. I hope it doesn't bother you too much. :-) -- Keir _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel |
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