[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [Xen-devel] Kernel printk timestamps and walltime drift

On 13/6/08 22:21, "Dan Magenheimer" <dan.magenheimer@xxxxxxxxxx> wrote:

> Hi Roger --
> Sorry, I made a bad assumption... the solution I provided
> works for hvm domains.  For pvm domains, the guest clock
> will generally be determined by xen system time, and as
> Keir said, if the underlying clock xen is using skews from
> wallclock time, then xen system time will skew also.
> I think the solution for this situation is to ensure
> that /proc/sys/xen/independent_wallclock is set to 0
> for each of your pvm domains and run ntpd on domain0.

Since sched_clock() is not built on top of xtime, this won't help.
sched_clock()'s implementation is tightly bound to Xen system time in our
Linux patchset. It could be changed, but really I think these timestamps are
the only noticeable artefact.

 -- Keir

Xen-devel mailing list



Lists.xenproject.org is hosted with RackSpace, monitoring our
servers 24x7x365 and backed by RackSpace's Fanatical Support®.