Re: [PATCH 01/18] io-controller: Documentation

From: Gui Jianfeng
Date: Tue May 05 2009 - 23:17:14 EST


Vivek Goyal wrote:
...
> + mount -t cgroup -o io,blkio none /cgroup
> +
> +- Create two cgroups
> + mkdir -p /cgroup/test1/ /cgroup/test2
> +
> +- Set weights of group test1 and test2
> + echo 1000 > /cgroup/test1/io.ioprio
> + echo 500 > /cgroup/test2/io.ioprio

Here seems should be /cgroup/test2/io.weight

> +
> +- Create two same size files (say 512MB each) on same disk (file1, file2) and
> + launch two dd threads in different cgroup to read those files. Make sure
> + right io scheduler is being used for the block device where files are
> + present (the one you compiled in hierarchical mode).
> +
> + echo 1 > /proc/sys/vm/drop_caches
> +
> + dd if=/mnt/lv0/zerofile1 of=/dev/null &
> + echo $! > /cgroup/test1/tasks
> + cat /cgroup/test1/tasks
> +
> + dd if=/mnt/lv0/zerofile2 of=/dev/null &
> + echo $! > /cgroup/test2/tasks
> + cat /cgroup/test2/tasks
> +
> +- At macro level, first dd should finish first. To get more precise data, keep
> + on looking at (with the help of script), at io.disk_time and io.disk_sectors
> + files of both test1 and test2 groups. This will tell how much disk time
> + (in milli seconds), each group got and how many secotors each group
> + dispatched to the disk. We provide fairness in terms of disk time, so
> + ideally io.disk_time of cgroups should be in proportion to the weight.
> + (It is hard to achieve though :-)).

--
Regards
Gui Jianfeng

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