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Re: [Xen-users] TAP:AIO much slower then file: ?!

To: Javier Guerra <javier@xxxxxxxxxxx>, xen-users@xxxxxxxxxxxxxxxxxxx
Subject: Re: [Xen-users] TAP:AIO much slower then file: ?!
From: MS <ms@xxxxxxxxxx>
Date: Thu, 31 Jul 2008 16:49:52 +0200
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Tastsite 440M needs over a hour with tap:aio:
If i use some more i have to wait .... to christmas :)
With file: the 440M need less then 3 minutes.

I know, 440M is not a good value, but it never can be less then 1% of the performance before changeing.

Javier Guerra schrieb:
On Thu, Jul 31, 2008 at 8:17 AM, MS <ms@xxxxxxxxxx> wrote:
Hi!

i checked the io performance with bonnie++ on an domU.
With "file:" i get a goot result (nearly the dom0 results):

that "440M" is the test size? if so, it sounds too small.  it should
at least be twice (5-10x is better) the size of cache available.
remember, "file:" devices might be cached by the Dom0, "tap:" won't.
with small files it's common to see this pattern on most tests, but
won't benefit most real world uses.




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