Messages in this thread | | | Date | Wed, 3 Aug 2011 15:38:03 +0800 | Subject | Re: fio posixaio performance problem | From | Shaohua Li <> |
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2011/8/3 Gui Jianfeng <guijianfeng@cn.fujitsu.com>: > 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 Hmm, the test runs always about 15M/s at my side regardless how many threads.
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