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Re: [Xen-devel] [PATCH] per-cpu time changes

On 8 Jul 2005, at 23:47, Don Fry wrote:

Here is another set of patches for the per-cpu timer changes to xen and
linux.  The patch is against today's xen-unstable-src.tgz.  This fixes
the occasional panic I was seeing on booting a slower system, and the
constant panic booting a fast system.  It has been tested UP and SMP on
an IBM summit system, and an IntelliStation.  The 'time went backwards'
messages are no longer seen.

Great! I'm cooking up a time patch to check in over the next few days -- it should handle the one remaining problem I see with your patch, that although 'guest time' will be monotonic on each individual cpu, they will diverge over time because percpu_ticks does not update local time w.r.t. a shared timebase. I think solving that necessarily means some bigger changes to how time is handled in Xen, and the interface to guests, and I'm currently merging those changes into the xenlinux tree (the Xen side is done and I can post an interim patch if that's interesting for anyone).

 -- Keir

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