Bug 1361654

Summary:	irqbalance with IRQBALANCE_BANNED_CPUS and isolcpus don't act intuitive
Product:	Red Hat Enterprise Linux 7	Reporter:	Andrej Manduch <amanduch>
Component:	irqbalance	Assignee:	Kairui Song <kasong>
Status:	CLOSED ERRATA	QA Contact:	Jiri Dluhos <jdluhos>
Severity:	unspecified	Docs Contact:
Priority:	unspecified
Version:	7.3	CC:	emcnabb, jdluhos, jeder, lmiksik, ruyang
Target Milestone:	rc
Target Release:	---
Hardware:	Unspecified
OS:	Unspecified
Whiteboard:
Fixed In Version:	irqbalance-1.0.7-12.el7	Doc Type:	If docs needed, set a value
Doc Text:		Story Points:	---
Clone Of:		Environment:
Last Closed:	2019-08-06 13:03:05 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:
Bug Depends On:
Bug Blocks:	1394638, 1472889, 1647768

Description Andrej Manduch 2016-07-29 16:06:57 UTC

Description of problem:

Few months ago in irqbalance was introduced feature which reads isolated cpu from kernel and don't assign interrupts to them.

Thing is that when you're using IRQBALANCE_BANNED_CPUS it also automatically disables this feature. Personally I think this is strange. Nevertheless I would suggest change this logic (I'm honestly not sure if logic behind this bahaviour is correct or not) or document this behaviour on man page. 


Version-Release number of selected component (if applicable):
irqbalance-1.0.7-8

Comment 3 Kairui Song 2018-11-05 09:56:14 UTC

In the commit ca5a3f13 and 2dddcfef which added autodetect and ban isolated CPUs, the commit message makes it very clear that IRQBALANCE_BANNED_CPUS will override the automatically detected banned_cpus, so it's intended to do so.
I'll update the man page so this will be no longer confusing.

Comment 6 Jiri Dluhos 2019-07-01 13:43:19 UTC

The man page is definitely improved - of course, the understandability is in the eye of the beholder - maybe it would be even clearer to add "If IRQBALANCE_BANNED_CPUS is specified, it will override the default exclusion of isolated and adaptive-tick CPUs." Will open a new bug for that, but even the current state is significantly better.

Comment 8 errata-xmlrpc 2019-08-06 13:03:05 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://access.redhat.com/errata/RHBA-2019:2179