From: Avi Kivity <avi@redhat.com>
To: "Hao, Xudong" <xudong.hao@intel.com>
Cc: "kvm@vger.kernel.org" <kvm@vger.kernel.org>
Subject: Re: KVM Test report, kernel 647e9e... qemu 7811d4...
Date: Fri, 26 Mar 2010 12:54:13 +0300 [thread overview]
Message-ID: <4BAC8445.4000205@redhat.com> (raw)
In-Reply-To: <EB8593BCECAB3D40A8248BE0B6400A38466287CA@shzsmsx502.ccr.corp.intel.com>
On 03/26/2010 11:39 AM, Hao, Xudong wrote:
>
> I checked cache=writeback parameter, the diotest performance is much worse than "no this parameter"(about 20 times).
>
> Followed qemu help, my command is "qemu-system-x86_64 -m 512 -smp 4 -net nic,macaddr=00:16:3e:79:0c:db,model=rtl8139 -net tap,script=/etc/kvm/qemu-ifup -hda /share/ltp_guest.img -drive cache=writeback", is it right?
>
> When booting guest with cache=writeback, there are some hdb drive Error printed in guest, and guest booting very slow.
>
>
You need to fold the -hda parameter into -driver, so the whole command
line becomes
qemu-system-x86_64 -m 512 -smp 4 -net nic,macaddr=00:16:3e:79:0c:db,model=rtl8139 -net tap,script=/etc/kvm/qemu-ifup -drive file=/share/ltp_guest.img,cache=writeback
-hda is deprecated, it forces cache=writethrough.
--
Do not meddle in the internals of kernels, for they are subtle and quick to panic.
next prev parent reply other threads:[~2010-03-26 9:54 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-03-08 6:40 KVM Test report, kernel 647e9e... qemu 7811d4 Hao, Xudong
2010-03-24 15:17 ` Avi Kivity
2010-03-26 8:39 ` Hao, Xudong
2010-03-26 9:54 ` Avi Kivity [this message]
2010-03-28 9:03 ` Hao, Xudong
2010-03-28 9:09 ` Avi Kivity
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