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 18:54:58 +0200 [thread overview]
Message-ID: <49CA61E2.3050400@redhat.com> (raw)
In-Reply-To: <A4758D2B-87DC-419A-86AD-7666A39E7961@yoderhome.com>
Kurt Yoder wrote:
>
> I upped the memory on the VM to 1 GB and ran the same test. It
> actually got *slower*:
>
> me@guest:~$ free
> total used free shared buffers cached
> Mem: 1024224 131324 892900 0 1816 18328
> -/+ buffers/cache: 111180 913044
> Swap: 488248 0 488248
> me@guest:~$ sudo -s
> me@guest:~# dd if=/dev/zero of=/bigfile count=100000
> 100000+0 records in
> 100000+0 records out
> 51200000 bytes (51 MB) copied, 22.2141 s, 2.3 MB/s
>
Wierd. Can you change the disk interface to ide to rule out virtio issues?
(though dd should be running entirely in cache)
Is your disk a raw volume or qcow file?
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2009-03-25 16:55 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
2009-03-25 16:51 ` Kurt Yoder
2009-03-25 16:54 ` Avi Kivity [this message]
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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