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Bug 1201552 - irqbalance should not place irqs on isolated CPUs
Summary: irqbalance should not place irqs on isolated CPUs
Keywords:
Status: CLOSED ERRATA
Alias: None
Product: Red Hat Enterprise Linux 7
Classification: Red Hat
Component: irqbalance
Version: 7.1
Hardware: Unspecified
OS: Unspecified
unspecified
unspecified
Target Milestone: rc
: ---
Assignee: Petr Holasek
QA Contact: Andrej Manduch
URL:
Whiteboard:
Depends On:
Blocks: 1175461 1244948
TreeView+ depends on / blocked
 
Reported: 2015-03-12 22:53 UTC by Rik van Riel
Modified: 2019-07-11 08:46 UTC (History)
12 users (show)

Fixed In Version: irqbalance-1.0.7-3.el7
Doc Type: Enhancement
Doc Text:
Cause: Irqbalance assigned IRQs also to isolated CPUs which are not under control of scheduler and usually used for some special dedicated purposes (HPC) Consequence: Perfomance of tasks running on isolated CPUs could be harm. Fix: Irqbalance parses isolated CPUs from kernel commandline Result: Irqbalance doesn't assign IRQs to isolated CPUs so task running there are not interfered.
Clone Of:
: 1244948 (view as bug list)
Environment:
Last Closed: 2015-11-19 05:21:34 UTC
Target Upstream Version:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Knowledge Base (Solution) 1534963 0 None None None 2017-07-05 08:53:11 UTC
Red Hat Product Errata RHBA-2015:2207 0 normal SHIPPED_LIVE irqbalance bug fix update 2015-11-19 08:17:13 UTC

Description Rik van Riel 2015-03-12 22:53:33 UTC 
Description of problem:

irqbalance can place IRQs on isolated CPUs, as specified with isolcpus= on the kernel commandline

Steps to Reproduce:
1. boot kernel with isolcpus=N-M  (to isolate cpus N-M)
2. start irqbalance
3. watch irqs get assigned to those CPUs, anyway

Expected results:

irqbalance is smart enough to skip assigning irqs to isolated cpus

Additional info:

I submitted a pull request for patches that add this functionality into upstream irqbalance:

https://github.com/Irqbalance/irqbalance/pull/19

This functionality should help keep maximum latencies down for realtime workloads on isolated cpus.
Comment 4 errata-xmlrpc 2015-11-19 05:21:34 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-2015-2207.html
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