Re: xen 3 clock (was Re: Panic with NetBSD 3.0 XENU)

[Manuel Bouyer <bouyer%antioche.eu.org@localhost>]

On Mon, Apr 17, 2006 at 10:21:22PM -0400, Jed Davis wrote:
> "Felipe Alfaro Solana" <felipe.alfaro%gmail.com@localhost> writes:
> 
> > get_tsc_offset_ns: tsc_delta=183617979 offset=612180549
> > get_tsc_offset_ns: tsc_delta=188671715 offset=629029656
> > get_tsc_offset_ns: tsc_delta=189550229 offset=631958613
> > get_tsc_offset_ns: tsc_delta=194527317 offset=648552176
> > get_tsc_offset_ns: tsc_delta=195652938 offset=652304985
> > get_tsc_offset_ns: tsc_delta=200779803 offset=669397903
> 
> As an aside: isn't this normal in Xen 3, since the shared time page is
> updated only once a second or so, instead of every tick?  If that's

Yes, this is perfectly normal for xen-3

> the case, I'll (or someone else can) update the DEBUG-conditioned
> sanity check in get_tsc_offset_ns that triggers that printf.

Please do, I'm not in a place from where I can commit right now

> We might also want to save a copy of the serial number of the time
> info, to skip unnecessarily copying it and recomputing stuff if it
> hasn't been updated.

You just have to make sure that the test+branch isn't slower than the copy :)

-- 
Manuel Bouyer <bouyer%antioche.eu.org@localhost>
     NetBSD: 26 ans d'experience feront toujours la difference
--