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Re: [Xen-devel] early_cpu_init() and identify_cpu()

To: "Keir Fraser" <Keir.Fraser@xxxxxxxxxxxx>, <xen-devel@xxxxxxxxxxxxxxxxxxx>
Subject: Re: [Xen-devel] early_cpu_init() and identify_cpu()
From: "Jan Beulich" <jbeulich@xxxxxxxxxx>
Date: Mon, 16 Jul 2007 07:41:06 +0100
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>I'd rather have a later call (but not that late -- before secondary CPUs
>come up is fine) than re-order start-of-day cpu detection code. At least in
>a first patchset! The MTRR update will still happen before scrolling needs
>to occur for the first time, and I don't see that the code will become
>spaghetti because of it.

Okay, will do it that way then.

>By the way, what makes you think that redrawing the whole screen (presumably
>re-pasting text characters one-by-one) would be faster than scrolling?
>Sounds slower to me, or is this because read-plus-write of UC memory sucks?

Yes, exactly that (really its presumably mostly the data dependency of the
writes on the reads, which in a write-only scenario is so much smaller).

>How much faster is scrolling of WC framebuffer on your test system?

Haven't tested yet, as I haven't made the adjustments to make WC work so far
(finding why it doesn't work was the last thing I did on Friday)... But as I 
said,
I don't expect much gain from *just* the attribute change, as reads will 
continue
to be done UC. As I said, I'm considering alternatives...

Jan


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