Messages in this thread | | | Date | Wed, 03 Aug 2011 13:12:23 +0800 | From | Gui Jianfeng <> | Subject | Re: fio posixaio performance problem |
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On 2011-8-3 12:47, Gui Jianfeng wrote: > 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
BTW, even if on Ext3, the problem is still there.
Thanks, Gui
> > Thanks, > Gui > >> >> Cheers, >> >> Dave. >
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