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Re: [Xen-devel] [PATCH] improve x86 page table handling performance

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Subject: Re: [Xen-devel] [PATCH] improve x86 page table handling performance
From: "Jan Beulich" <jbeulich@xxxxxxxxxx>
Date: Tue, 27 Mar 2007 07:22:30 +0100
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>>> "Jan Beulich" <jbeulich@xxxxxxxxxx> 26.03.07 16:50 >>>
>Where possible,
>- use hypercalls instead of writing to read-only pages
>- fold TLB flushes into page table update hypercalls
>- on PAE, use single-access updates instead of two-access ones
>The single change to pte_clear() yields a 25-30% boost for kernel builds
>on a 4x2x2 CPUs, 8Gb box; the other changes together yield improvements
>of 2-5%.

I shall clarify that this is for the PAE case only (i.e. resulting from the
folding of two page faults into a single hypercall, which is being used in the
kmap path).


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