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Bug 1165580 - blkiotune value should be consistent with value in cgroup
Summary: blkiotune value should be consistent with value in cgroup
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: libvirt
Version: 7.1
Hardware: Unspecified
OS: Unspecified
medium
medium
Target Milestone: rc
: ---
Assignee: Martin Kletzander
QA Contact: Virtualization Bugs
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2014-11-19 09:28 UTC by Pei Zhang
Modified: 2015-11-19 05:56 UTC (History)
5 users (show)

Fixed In Version: libvirt-1.2.17-7.el7
Doc Type: Bug Fix
Doc Text:
Clone Of:
Environment:
Last Closed: 2015-11-19 05:56:25 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHBA-2015:2202 0 normal SHIPPED_LIVE libvirt bug fix and enhancement update 2015-11-19 08:17:58 UTC

Description Pei Zhang 2014-11-19 09:28:47 UTC 
Description of problem:
a maximum value can be set by blkiotune , but can not be checked in cgroup.

Version-Release number of selected component (if applicable):
kernel-3.10.0-203.el7.x86_64
qemu-kvm-rhev-2.1.2-8.el7.x86_64
libvirt-1.2.8-6.el7.x86_64

How reproducible:
100%

Steps to Reproduce:
# virsh list 
 Id    Name                           State
----------------------------------------------------
 29    r7                             running

1> for device_read/write_iops_sec , set value=4294967295 , set successfully. but can not be checked in cgroup.

1.1> set the value and check using blkiotune command

# virsh blkiotune r7 --device-read-iops-sec /dev/sda,4294967295 --device-write-iops-sec /dev/sda,4294967295

[root@184 ~]# virsh blkiotune r7
weight         : 500
device_weight  : 
device_read_iops_sec: /dev/sda,4294967295
device_write_iops_sec: /dev/sda,4294967295
device_read_bytes_sec: 
device_write_bytes_sec: 

1.2> check the value in the cgroup , it has nothing
# cat /sys/fs/cgroup/blkio/machine.slice/machine-qemu\\x2dr7.scope/blkio.throttle.read_iops_device 

# cat /sys/fs/cgroup/blkio/machine.slice/machine-qemu\\x2dr7.scope/blkio.throttle.write_iops_device 

2> for device_read/write_bytes_sec , set value= 18446744073709551615, set successfully. but can not be checked in cgroup.

2.1> set the value and check using blkiotune command

# virsh blkiotune r7 --device-read-bytes-sec /dev/sda,18446744073709551615 --device-write-bytes-sec /dev/sda,18446744073709551615 

# virsh blkiotune r7
weight         : 500
device_weight  : 
device_read_iops_sec: /dev/sda,4294967295
device_write_iops_sec: /dev/sda,4294967295
device_read_bytes_sec: /dev/sda,18446744073709551615
device_write_bytes_sec: /dev/sda,18446744073709551615

2.2> check the value in cgroup , it has nothing
# cat /sys/fs/cgroup/blkio/machine.slice/machine-qemu\\x2dr7.scope/blkio.throttle.read_bps_device 
# cat /sys/fs/cgroup/blkio/machine.slice/machine-qemu\\x2dr7.scope/blkio.throttle.write_bps_device 
 
3>check domain XML , it has the value .
# virsh dumpxml r7 | grep blkiotune -A 8
  <blkiotune>
    <device>
      <path>/dev/sda</path>
      <read_iops_sec>4294967295</read_iops_sec>
      <write_iops_sec>4294967295</write_iops_sec>
      <read_bytes_sec>18446744073709551615</read_bytes_sec>
      <write_bytes_sec>18446744073709551615</write_bytes_sec>
    </device>
  </blkiotune>


Actual results:
As above , the value can be set by blkiotune and set successfully in the domain XML , but it has nothing in cgroup.

Expected results:
the value set by blkiotune can be checked in cgroup.

Additional info:
Comment 1 Martin Kletzander 2015-08-03 14:57:05 UTC 
Patch proposed upstream:

https://www.redhat.com/archives/libvir-list/2015-August/msg00065.html
Comment 4 Pei Zhang 2015-09-11 09:25:22 UTC 
Verified version:
libvirt-1.2.17-8.el7.x86_64
qemu-kvm-rhev-2.3.0-22.el7.x86_64

verified steps:

1.define and start a guest, check blkiotune value.
# virsh blkiotune r72
weight         : 1000
device_weight  : 
device_read_iops_sec: 
device_write_iops_sec: 
device_read_bytes_sec: 
device_write_bytes_sec: 

1.1. set a iops value that kernel accepts, but does not set them.

set the value 
# virsh blkiotune r72 --device-read-iops-sec /dev/sdb,4294967295

get the value via blkiotune 
# virsh blkiotune r72
weight         : 1000
device_weight  : 
device_read_iops_sec: 
device_write_iops_sec: 
device_read_bytes_sec: 
device_write_bytes_sec: 

check in cgroup, Nothing ouput 
# cat /sys/fs/cgroup/blkio/machine.slice/machine-qemu\\x2dr72.scope/blkio.throttle.read_iops_device 

check domian xml, Nothing output.
# virsh dumpxml r72 | grep blkiotune -A 3


1.2 set a normal value that kernel accpets and will set them in cgroup.

# virsh blkiotune r72 --device-read-iops-sec /dev/sdb,4294967294

check in cgroup
# cat /sys/fs/cgroup/blkio/machine.slice/machine-qemu\\x2dr72.scope/blkio.throttle.read_iops_device 
8:16 4294967294

check via blkiotune 

# virsh blkiotune r72
weight         : 1000
device_weight  : 
device_read_iops_sec: /dev/sdb,4294967294
device_write_iops_sec: 
device_read_bytes_sec: 
device_write_bytes_sec: 

check in domian xml :
# virsh dumpxml r72 | grep blkiotune -A 3
  <blkiotune>
    <device>
      <path>/dev/sdb</path>
      <read_iops_sec>4294967294</read_iops_sec>
--
  </blkiotune>

2. set a bps value that kernel accepts, but does not set them.

# virsh blkiotune r72 --device-write-bytes-sec /dev/sdb,18446744073709551615

get the value via blkiotune 

# virsh blkiotune r72
weight         : 1000
device_weight  : 
device_read_iops_sec: 
device_write_iops_sec: 
device_read_bytes_sec: 
device_write_bytes_sec: 

check in cgroup, Nothing ouput 
# cat /sys/fs/cgroup/blkio/machine.slice/machine-qemu\\x2dr72.scope/blkio.throttle.write_bps_device 

check domian xml, Nothing output.
# virsh dumpxml r72 | grep blkiotune -A 3


2.1 set a normal value that kernel accpets and will set them in cgroup.

# virsh blkiotune r72 --device-write-bytes-sec /dev/sdb,18446744073709551614

check in cgroup 

# cat /sys/fs/cgroup/blkio/machine.slice/machine-qemu\\x2dr72.scope/blkio.throttle.write_bps_device 
8:16 18446744073709551614

check via blkiotune 

# virsh blkiotune r72
weight         : 1000
device_weight  : 
device_read_iops_sec: 
device_write_iops_sec: 
device_read_bytes_sec: 
device_write_bytes_sec: /dev/sdb,18446744073709551614

check in domain xml 
# virsh dumpxml r72 | grep blkiotune -A 5
  <blkiotune>
    <device>
      <path>/dev/sdb</path>
      <write_bytes_sec>18446744073709551614</write_bytes_sec>
    </device>
  </blkiotune>

Also tested with lxc using same steps as above.

Now the values set via blkiotune are in sync with cgroup. 

Move to verified.
Comment 6 errata-xmlrpc 2015-11-19 05:56:25 UTC 
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHBA-2015-2202.html
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