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Re: [Xen-devel] [PATCH] Adjust time init sequence

To: "Tian, Kevin" <kevin.tian@xxxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH] Adjust time init sequence
From: Keir Fraser <keir.fraser@xxxxxxxxxxxxx>
Date: Fri, 12 Dec 2008 09:08:30 +0000
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On 12/12/2008 03:40, "Tian, Kevin" <kevin.tian@xxxxxxxxx> wrote:

> A temp workaround is to move rdtscll(t->local_tsc_stamp) into
> calibrate_tsc_bp, which gives a sane NOW() before percpu time
> init. But then the purpose behind is ambiguous... why would we
> want to count system time from this point? If we can't count
> system time starting from power on, it looks clearer to tag system
> time as 0 when initializing wc_sec/wc_nsec by do_settime.
> Actually the starting point of xen system time is not that critical
> since it's mostly used by relative progress. Then my previous
> updated patch can be used? :-)

How about rdtscll(t->local_tsc_stamp) at the top of init_xen_time(), and
remove the one I added to early_time_init()? That would allow NOW() usage at
least in init_xen_time(), and be later than the TSC reset.

 -- Keir

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