Bug 1238589

Summary: iothreadinfo cannot be used
Product: Red Hat Enterprise Linux 7 Reporter: Luyao Huang <lhuang>
Component: libvirtAssignee: Peter Krempa <pkrempa>
Status: CLOSED ERRATA QA Contact: Virtualization Bugs <virt-bugs>
Severity: medium Docs Contact:
Priority: medium    
Version: 7.2CC: dyuan, hhan, honzhang, mzhan, rbalakri
Target Milestone: rc   
Target Release: ---   
Hardware: x86_64   
OS: Linux   
Whiteboard:
Fixed In Version: libvirt-1.2.17-2.el7 Doc Type: Bug Fix
Doc Text:
Story Points: ---
Clone Of: Environment:
Last Closed: 2015-11-19 06:47:57 UTC Type: Bug
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description Luyao Huang 2015-07-02 08:39:26 UTC
Description of problem:
iothreadinfo cannot be used

Version-Release number of selected component (if applicable):
libvirt-1.2.17-1.el7.x86_64

How reproducible:
100%

Steps to Reproduce:
1.prepare a running guest with iothread 
# virsh dumpxml test4
<domain type='kvm' id='8'>
  <name>test4</name>
  <uuid>b1e7936b-104b-430e-9211-d6c61b8df313</uuid>
  <memory unit='KiB'>1024000</memory>
  <currentMemory unit='KiB'>1024000</currentMemory>
  <vcpu placement='static' current='2'>4</vcpu>
  <iothreads>2</iothreads>
  <cputune>
    <emulatorpin cpuset='2'/>
    <iothreadpin iothread='1' cpuset='3'/>
  </cputune>


2. use iothreadinfo

# virsh iothreadinfo test4
error: Unable to get domain IOThreads information
error: Unable to encode message payload

3.

Actual results:
iothreadinfo cannot be used in new version

Expected results:
can get output

Additional info:

V1 of this issue's patch:
https://www.redhat.com/archives/libvir-list/2015-June/msg01523.html

Comment 1 Peter Krempa 2015-07-02 14:55:43 UTC
Improved patchset:

http://www.redhat.com/archives/libvir-list/2015-July/msg00138.html

Comment 2 Peter Krempa 2015-07-08 09:07:37 UTC
Fixed upstream:

commit e8c5f61e91025f244bb022b1774a3fc6484625f8
Author: Peter Krempa <pkrempa>
Date:   Thu Jul 2 16:46:46 2015 +0200

    util: bitmap: Don't alloc overly large binary bitmaps
    
    Optimize the virBitmap to array-of-char bitmap conversion by skipping
    trailing zero bytes.
    
    This also fixes a regression when requesting iothread information from a
    live VM since after commit 825df8c3158cfaf5f398418471f10f4ff3c3515a the
    bitmap returned from virProcessGetAffinity is too big to be formatted
    properly via RPC. A user would get the following error:
    
    error: Unable to get domain IOThreads information
    error: Unable to encode message payload

Comment 5 Han Han 2015-09-11 07:08:46 UTC
Hi Peter, I can reproduce it on libvirt-1.2.17-1.el7.x86_64
Verify it on libvirt-1.2.17-8.el7.x86_64

Step1:
Define a domain fllowing in xml:
...
 <vcpu placement='static' current='2'>4</vcpu>
  <iothreads>2</iothreads>
  <cputune>
    <emulatorpin cpuset='2'/>
    <iothreadpin iothread='1' cpuset='3'/>
  </cputune>
...


Step2:
When domain shutoff, run iothreadinfo:
# virsh iothreadinfo t38
 IOThread ID     CPU Affinity   
---------------------------------------------------
 1               3
 2               0-7


Step3:
Start domain and run iothreadinfo with --live:

# virsh start t38
Domain t38 started

# virsh iothreadinfo t38 --live
 IOThread ID     CPU Affinity   
---------------------------------------------------
 1               3
 2               0-7

Comment 7 errata-xmlrpc 2015-11-19 06:47:57 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