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Re: [Xen-devel] open/stat64 syscalls run faster on Xen VM than standard

To: "Petersson, Mats" <mats.petersson@xxxxxxx>
Subject: Re: [Xen-devel] open/stat64 syscalls run faster on Xen VM than standard Linux
From: xuehai zhang <hai@xxxxxxxxxxxxxxx>
Date: Mon, 28 Nov 2005 09:28:31 -0600
Cc: Xen Mailing List <xen-devel@xxxxxxxxxxxxxxxxxxx>
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Petersson, Mats wrote:
-----Original Message-----
From: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx [mailto:xen-devel-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of Anthony Liguori
Sent: 28 November 2005 14:39
To: xuehai zhang
Cc: Xen Mailing List
Subject: Re: [Xen-devel] open/stat64 syscalls run faster on Xen VM than standard Linux

This may just be the difference between having the extra level of block caching from using a loop back device.

Try running the same benchmark on a domain that uses an actual partition. While the syscalls may appear to be faster, I imagine it's because the cost of pulling in a block has already been payed so the overall workload is unaffected.


And this would be the same as running standard linux with the loopback
file-system mounted and chroot to the local file-system, or would that
be different? [I'm asking because I don't actually understand enough
about how it works to know what difference it makes, and I would like to
know, because at some point I'll probably need to know this.]

Mats,
I will do this experiments and see what is happening (as I promised in the 
popen threads).
Thanks.
Xuehai

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