Re: [Qemu-devel] [PATCH 0/7] qcow2: Reduce the number of I/O ops when doing COW

[Alberto Garcia]

On Fri 26 May 2017 03:32:49 PM CEST, Anton Nefedov wrote:
>>> address@hidden ~]# fio --name=randwrite --blocksize=4k
>>> --filename=/dev/sdb --rw=randwrite --direct=1 --ioengine=libaio
>>> --size=2g --io_size=32m
>> 
>> In my tests I sometimes detected slight performance decreases in that
>> HDD scenario but using 'write' instead of 'randwrite' (and --runtime=60
>> instead of --io_size).
>> 
>> Can you try and see how that works for you?
>
> For me it keeps giving pretty much the same result before and after
>
>   write: io=512736KB, bw=8545.4KB/s, iops=2136, runt= 60004msec

Ok, that's the expected behavior. Good!

Berto