On 3/12/18 7:59 PM, wk wrote:
> Hi, axboe:
>
> Sorry for write email to you directly.
>
> I have a question about fio. I want generate a write sequence:
> first write: 0-8KB
> second write: 4-12KB
> third write : 8-16KB
> forth wirte: 12-20KB
> fifth write: 16KB-24KB
>
> Each io is 8KB, and next io offset is 4KB. How to write the fio command?
> I test "fio --ioengine=libaio --direct=1 --rw=randwrite --number_ios=4 --norandommap --randrepeat=0 --iodepth=1 --size=100% --numjobs=1 --bs=8k --filename=/dev/nvme0n1 --loops=1 --blockalign=4096 --debug=io --name=DI_Stress", but it seems each io offset is multiple of 4KB.But it is not overlap last 8KB writed block.
>
> I also test "fio --ioengine=libaio --direct=1 --rw=write --number_ios=4 --norandommap --randrepeat=0 --iodepth=1 --size=100% --numjobs=1 --bs=8k --filename=/dev/nvme0n1 --loops=1 --blockalign=4096 --debug=io --name=DI_Stress", but it seems each io offset is multiple of 4KB.But it is not overlap IO. Some fio log is below:
> io complete: io_u 0x1f21600: off=0/len=8192/ddir=1io
> io complete: io_u 0x1f21600: off=8192/len=8192/ddir=1io
> io complete: io_u 0x1f21600: off=16384/len=8192/ddir=1io
> io complete: io_u 0x1f21600: off=24576/len=8192/ddir=1io
> I want change the red offset address '0/8192/16384/24576' to '0/4096/8192/12288' by change my FIO command.
Don't email me directly, I've CC'ed the proper list.
You're supposed to be able to do that with:
bs=8k
rw=write:-4k
which will write 0..8k, 4..12k, etc. But there's a bug there, so you need to
update to latest -git first, it needs this commit:
commit 69b98f11d62cb12482130fac79b8ebf00c0bb139
Author: Jens Axboe <axboe@xxxxxxxxx>
Date: Tue Mar 13 11:49:55 2018 -0600
io_u: only rewind file position if it's non-zero
and it should work for you.
--
Jens Axboe
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