lxc.cgroup.blkio.weight not having expected effect

[David Parks]

I've got 2 LXC containers with these cgroup settings:

lxc.cgroup.blkio.weight = 200

lxc.cgroup.cpu.shares = 200

 

and

 

lxc.cgroup.blkio.weight = 800

lxc.cgroup.cpu.shares = 800

 

I have verified in /sys/fs/cgroup/blkio/lxc/test1-lxccontainer/blkio.weight
is indeed set to 200 on the host OS.

I have verified that cpu.shares are split up 80% to container 1 and 20% to
container 2.

But when I run this command in both containers:

# write a 10GB file to disk

dd bs=1M count=10000 if=/dev/zero of=1test conv=fdatasync

 

Or a similar test on reads:

davidparks21 at test-cgroups1:/tmp$ time sh -c "dd if=1test of=/dev/null bs=1M"

10000+0 records in

10000+0 records out

10485760000 bytes (10 GB) copied, 37.9176 s, 277 MB/s

 

real    0m37.939s

user    0m0.004s

sys     0m24.306s

 

The IO speeds see in iotop on the host OS are virtually the same between the
two containers.

I expected to see container 2 command 80% of the IO access in this case.

 

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