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Date: Mon, 11 Nov 2013 11:15:59 +0100
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [PATCH 2/2] exec: make address spaces 64-bit wide
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To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: lcapitulino@redhat.com, qemu-devel@nongnu.org, marcel.a@redhat.com

Il 10/11/2013 11:31, Michael S. Tsirkin ha scritto:
> > Reported-by: Luiz Capitulino <lcapitulino@redhat.com>
> > Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
> 
> So this causes a 12% performance regression on some TCG
> tests, I think we should look into a smarter
> datastructure to solve the issues.

It causes a 12% performance regression in a single testcase where KVM
has a 150x performance regression.  This says a lot about the relevance
of the testcase.

In any case, I have patches to avoid the regression.  For 1.7 we can
just revert the patches, for 1.8 we can apply this patch together with
the optimizations that avoid introducing a regression.

Paolo