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Date: Fri, 12 Mar 2010 22:40:41 +0000
From: Jamie Lokier <jamie@shareable.org>
Subject: Re: [Qemu-devel] [PATCH QEMU] transparent hugepage support
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To: Andrea Arcangeli <aarcange@redhat.com>
Cc: Avi Kivity <avi@redhat.com>, Paul Brook <paul@codesourcery.com>, qemu-devel@nongnu.org

Andrea Arcangeli wrote:
> On Fri, Mar 12, 2010 at 06:41:56PM +0000, Paul Brook wrote:
> > Doesn't non-PAE (i.e. most 32-bit x86) use 4M huge pages? There's still a good 
> > number of those knocking about.
> 
> Yep, but 32bit x86 host won't support transparent hugepage (certain
> bits overflows in the kernel implementation, there's no more space in
> the page struct). It's not worth it IMHO.

Perhaps the performance figures would be even more significant for
32-bit x86 than 64-bit, due to the smaller TLBs.

I guess that's not what you mean by worth it?

-- Jamie