Messages in this thread | | | Date | Wed, 3 Aug 2011 16:22:50 +0800 | Subject | Re: fio posixaio performance problem | From | Shaohua Li <> |
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2011/8/3 Gui Jianfeng <guijianfeng@cn.fujitsu.com>: > On 2011-8-3 15:38, Shaohua Li wrote: >> 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. > > CFQ? yes.
> what's the slice_idle value? default value. I didn't change it. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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