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Date: Tue, 06 Apr 2010 12:57:01 +0300
From: Avi Kivity <avi@redhat.com>
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Subject: Re: [PATCH 00 of 41] Transparent Hugepage Support #17
References: <patchbomb.1270168887@v2.random> <20100405120906.0abe8e58.akpm@linux-foundation.org> <20100405193616.GA5125@elte.hu> <n2j84144f021004051326mab7cd8fbm949115748a3d78b6@mail.gmail.com> <alpine.LFD.2.00.1004051326380.21411@i5.linux-foundation.org> <t2q84144f021004051346o65f03e71r5b7bb19b433ce454@mail.gmail.com> <alpine.LFD.2.00.1004051347480.21411@i5.linux-foundation.org> <20100405232115.GM5825@random.random> <alpine.LFD.2.00.1004051636060.21411@i5.linux-foundation.org> <20100406011345.GT5825@random.random> <alpine.LFD.2.00.1004051836000.5870@i5.linux-foundation.org> <alpine.LFD.2.00.1004051917310.3487@i5.linux-foundation.org> <4BBB052D.8040307@redhat.com>
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On 04/06/2010 12:55 PM, Avi Kivity wrote:
>
> Here is a microbenchmark demonstrating the hit (non-virtualized); it 
> simulates a pointer-chasing application with a varying working set.  
> It is easy to see when the working set overflows the various caches, 
> and later when the page tables overflow the caches.  For 
> virtualization the hit will be a factor of 3 instead of 2, and will 
> come earlier since the page tables are bigger.
>
>  size   4k (ns)    2M (ns)
>    4k       4.9        4.9
>   16k       4.9        4.9
>   64k       7.6        7.6
>  256k      15.1        8.1
>    1M      28.5       23.9
>    4M      31.8       25.3
>   16M      94.8       79.0
>   64M     260.9      224.2
>  256M     269.8      248.8
>    1G     278.1      246.3
>    4G     330.9      252.6
>   16G     436.3      243.8
>   64G     486.0      253.3
>


(latencies are for a single read access)

-- 
error compiling committee.c: too many arguments to function

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