Re: fio posixaio performance problem

[Gui Jianfeng]

On 2011-8-3 12:06, Dave Chinner wrote:
> On Wed, Aug 03, 2011 at 11:40:04AM +0800, Gui Jianfeng wrote:
>> Hi,
>>
>> I ran a fio test to simulate qemu-kvm io behaviour.
>> When job number is greater than 2, IO performance is
>> really bad.
>>
>> 1 thread: aggrb=15,129KB/s
>> 4 thread: aggrb=1,049KB/s
>>
>> Kernel: lastest upstream
>>
>> Any idea?
>>
>> ---
>> [global]
>> runtime=30
>> time_based=1
>> size=1G
>> group_reporting=1
>> ioengine=posixaio
>> exec_prerun='echo 3 > /proc/sys/vm/drop_caches'
>> thread=1
>>
>> [kvmio-1]
>> description=kvmio-1
>> numjobs=4
>> rw=write
>> bs=4k
>> direct=1
>> filename=/mnt/sda4/1G.img
> 
> What filesystem?

Ext4

Thanks,
Gui

> 
> Cheers,
> 
> Dave.


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