[Xen-devel] Re: [PATCH] trust new architecturally-defined TSC Invariant bit on Intel systems

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

On 09/10/2009 20:03, "Dan Magenheimer" <dan.magenheimer@xxxxxxxxxx> wrote:

> Actually it did (avoid rendezvous), but I have to admit
> it was accidental: I was trying to avoid the write_tsc's
> not the rendezvous, and I didn't notice the additional
> implication until I was looking at the difference between
> my patch and yours.
> 
> I'll look at this more in a few days...

If you mean your test-and-goto in time_calibration_tsc_rendezvous(), that
was just broken. You still raised the TIME_CALIBRATE_SOFTIRQ, but with
uninitialised r->master_stime. And at that point you'd already rendezvoused
all the CPUs, so done the expensive bit anyway.

 -- Keir



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