From: Avi Kivity <avi@redhat.com>
To: Kurt Yoder <ktykvm@yoderhome.com>
Cc: kvm@vger.kernel.org
Subject: Re: IO on guest is 20 times slower than host
Date: Wed, 25 Mar 2009 18:35:31 +0200 [thread overview]
Message-ID: <49CA5D53.1080401@redhat.com> (raw)
In-Reply-To: <4AC00930-1EBB-4704-94CF-29478D07F03A@yoderhome.com>
Kurt Yoder wrote:
>>
>> I get 141 MB/s on the same test (it only copies to memory anyway).
>> Is your VM under memory pressure?
>
> I don't think so. The host has 128 GB of memory, and even the
> pre-emptive kernel caching doesn't come close to filling it:
>
> me@host:~$ free
> total used free shared buffers cached
> Mem: 132043960 1742480 130301480 0 84628 826040
> -/+ buffers/cache: 831812 131212148
> Swap: 1048568 0 1048568
>
> My /tmp should be physical disk in both cases. To be thorough, I also
> ran the test while writing the output file to /, and got the same
> results (5.7 MB/s on guest, 144 MB/s on host).
Your guest is only assigned 256MB though.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2009-03-25 16:35 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-03-25 15:23 IO on guest is 20 times slower than host Kurt Yoder
2009-03-25 16:13 ` Avi Kivity
2009-03-25 16:28 ` Kurt Yoder
2009-03-25 16:35 ` Avi Kivity [this message]
2009-03-25 16:51 ` Kurt Yoder
2009-03-25 16:54 ` Avi Kivity
2009-03-25 17:11 ` Kurt Yoder
2009-03-25 17:55 ` Avi Kivity
2009-03-25 18:51 ` Kurt Yoder
2009-03-26 10:16 ` Avi Kivity
2009-03-27 13:53 ` Kurt Yoder
2009-03-27 14:03 ` Kurt Yoder
2009-03-27 14:10 ` Kurt Yoder
2009-03-29 14:29 ` Avi Kivity
2009-03-29 19:10 ` Avi Kivity
2009-03-31 9:59 ` Joerg Roedel
2009-03-31 10:02 ` Avi Kivity
2009-04-04 11:47 ` Avi Kivity
2009-03-30 19:39 ` Kurt Yoder
2009-03-31 15:15 ` Kurt Yoder
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