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SubjectRe: [PATCH 0/2] dm-ioband: I/O bandwidth controller v1.7.0: Introduction
Hi Dong-Jae,

Thanks for being intersted in dm-ioband.

> I tested dm-ioband( the latest release, ver 1.7.0 ) IO controller, but
> I had a strange result from it.
> I have something wrong in test process?
> The test process and results are in attached file.
> Can you check my testing result and give me a helpful advices and comments?

There are some suggestions for you.

1. you have to specify a dm-ioband device at the command line to
control bandwidth.

# tiotest -R -d /dev/mapper/ioband1 -f 300

2. tiotest is not an appropriate tool to see how bandwith is shared
among devices, becasue those three tiotests don't finish at the
same time, a process which issues I/Os to a device with the highest
weight finishes first, so you can't see how bandwidth is shared
from the results of each tiotest.

I use iostat to see the time variation of bandiwdth. The followings
are the outputs of iostat just after starting three tiotests on the
same setting as yours.

# iostat -p dm-0 -p dm-1 -p dm-2 1
Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
dm-0 5430.00 0.00 10860.00 0 10860
dm-1 16516.00 0.00 16516.00 0 16516
dm-2 32246.00 0.00 32246.00 0 32246

avg-cpu: %user %nice %system %iowait %steal %idle
0.51 0.00 21.83 76.14 0.00 1.52

Device: tps Blk_read/s Blk_wrtn/s Blk_read Blk_wrtn
dm-0 5720.00 0.00 11440.00 0 11440
dm-1 16138.00 0.00 16138.00 0 16138
dm-2 32734.00 0.00 32734.00 0 32734

> You can refer the testing tool, tiobench, in
> Originally, tiobench don't support the direct IO mode testing, so I
> added the O_DIRECT option to tiobench source code and recompile it to
> test the Direct IO cases

Could you give me the O_DIRECT patch?

Ryo Tsuruta

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