linux-kernel - Re: [PATCH 0/3] Virtual huge zero page

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Date:	Mon, 01 Oct 2012 10:33:12 -0700
From:	"H. Peter Anvin" <hpa@...ux.intel.com>
To:	Andrea Arcangeli <aarcange@...hat.com>
CC:	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
	Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
	Andi Kleen <ak@...ux.intel.com>, linux-kernel@...r.kernel.org,
	"Kirill A. Shutemov" <kirill@...temov.name>,
	Arnd Bergmann <arnd@...db.de>, Ingo Molnar <mingo@...nel.org>,
	linux-arch@...r.kernel.org
Subject: Re: [PATCH 0/3] Virtual huge zero page

On 10/01/2012 10:26 AM, Andrea Arcangeli wrote:
> 
>> It is well known that microbenchmarks can be horribly misleading.  What
>> led to Kirill investigating huge zero page in the first place was the
>> fact that some applications/macrobenchmarks benefit, and I think those
>> are the right thing to look at.
> 
> The whole point of the two microbenchmarks was to measure the worst
> cases for both scenarios and I think that was useful. Real life using
> zero pages are going to be somewhere in that range.
> 

... and I think it would be worthwhile to know which effect dominates
(or neither, in which case it doesn't matter).

Overall, I'm okay with either as long as we don't lock down 2 MB when
there isn't a huge zero page in use.

	-hpa

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