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. -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
